Showing posts with label airline. Show all posts
Showing posts with label airline. Show all posts
March 17, 2012

Terminal Leave and the American Aerotropolis

In the military some people build up their leave balances and have 45 days of leave at the end of their enlistment; they can request "terminal leave" - they depart 45 days early, they're gone and free, walking away to whatever they choose as their next. Of course, the military is a rational organization, and they only let you leave if they can afford it. There are priorities.




Recognized by many as a trenchant contribution, the Washington Monthly's article Terminal Sickness, subtitled How a thirty-year-old policy of deregulation is slowly killing America’s airline system—and taking down Cincinnati, Memphis, and St. Louis with it. is a worthy read.

A tale of Two Khans: Small bit of interweb hyperlink-irony: we note that while co-author Lina Khan is no relation of Alfred Kahn, the father of airline deregulation who openly admitted he didn't understand aviation and couldn't tell the different models of airplanes apart - he famously saw them all as "marginal costs with wings" - a comparison of Alfred Kahn's and Lina Khan's presence speaks clearly about the changes in America over the time gap between Then and Now. (Then is dead, long live the Now.) (edit: spelling corrected)

Terminal Sickness decries the unexpected consequences of 1978 airline deregulation and the subsequent abdication of anti-trust enforcement. "Trust" is a passe term dating from when it was difficult to get a corporate charter, and I hope you get to hear more of the term 'trust' and less of the word 'tryst" over the next few years.

The overt evidence of deregulation's unexpected consequence is the effect of unregulated airline behavior on the economies of Cincinatti, Memphis, St. Louis, Pittsburgh, and Cleveland. (Actually, the Cleveland debacle is just about to take place as municipal subsidies expire and the United-Continental merger and reduction render the legacy Cleveland operation redundant.)

Local governments have invested treasure and incurred long-term debt in order to build the terminals that airlines need; the federal government spends even more on the runways, navigation facilities, and aviation infrastructure that delivers the airplanes to the local government's terminal.

Our common wealth is invested in long term obligations to provide the (aviation) transport that successful modern cities require. Let's be clear that vibrant air service is a public good, a public need, and even - gasp - a public utility.

However, the unregulated behavior of the airlines puts airline service completely under the sway of (short-term) investors who are not motivated to consider the fortunes of the airport authorities that provide their facilities or the public that funds them. In fact, as they whip-saw airports against each other, airlines have found it marginally profitable to drive airports to the brink and into ruin - in the same relentless way they have extracted wealth from their pensions, employees, and customers.

Although deregulation took the government out finessing the airlines, the airlines still very much tweak the government. For instance, bankruptcy: over the last twenty years airlines have gone into strategic bankruptcies to protect their assets and cut their liabilities, voiding long-term costs and contracts and moving their pension expenses from their own balance sheets into the Pension Benefit Guaranty Corporation, which is essentially you and me. In deregulation, government didn't abandon aviation, it just gave up the benefits of influence while retaining the costs.

In many ways, the results of thirty years of airline deregulation should be a tocsin for those who would deregulate other public utilities (energy, transport, etc). Instead the cities abandoned and abused by the airlines invoke the serenity prayer and regard their mistreatment as the result of unfortunate and impersonal market forces, when in fact they are the result of intentional calculation by the airline industry.

So let's be clear on that: in general, what happens in the airline industry is intentional. Your cancelled flight? Their inability to put you on the next plane? Selling 105 tickets for a 100 seat airplane? Your time lost in delays boarding? Scheduling 90 airplanes departures in a time period where only 60 can actually leave in perfect conditions? Those are all airline business decisions, and in general the benefits accrue to the investors and the costs are born by - well, you and me.

Cities and regions need robust, distributed and competitive air service for their economic viability. We regulate gas and electrical utilities, cable companies and phone companies, farm prices and production - because the industry relies on the public and the public relies on the industry, and regulation is mutually beneficial. We can't tolerate the undampened effect of the business cycle (again with the K-waves?) on the dependent population, especially when the business cycle depends on public investment for its infrastructure. Regulation is civilized.

The article is excellent and I recommend it to you. I particularly enjoy the article's exposition of the railroad experience as precursor to today's aviation environment, and I was amused to find myself contemplating the parallels while riding my bicycle on the bike trail, which is itself an artifact of boom-and-bust railroad investment.

For those kind few still reading - and I am grateful - a few more thoughts about airlines and government, and then in a later post we'll move on to what may be the underlying issue.

Forget Metropolis. Think Aerotropolis


The next new trend in urban economic development is the Aerotropolis, a city-airport duality. According to Dr. John D. Kasarda, "Airports will shape business location and urban development in the 21st century as much as highways did in the 20th century, railroads in the 19th and seaports in the 18th". (see, Aerotropolis.com/)

The perfect situation for an Aerotropolis is a legacy city center with vertical development and the prerequisite mass of the creative class, paired with a geographically removed major airport and connected by multi-modal, high-speed transport (highways, trains, helicopters). A textbook depiction of an area ripe for development as an Aerotroplis might look like this:



In the generic model, a legacy city center with developed education and research facilities, and with robust highway, river and train logistics, connects to a slightly removed major airport by a high-speed corridor of highways and mass transit. Movement between the two nodes needs to be almost frictionless*. The Aerotropolis shows that wealth and growth will occur along the highway connector and around the airport.

So that brings a few new requirements into pragmatic development. The city center and the airport need to be in the same government structure, either City or County, in order for them to share common incentives. No one party can build the Aerotropolis unilaterally; it takes government, business, and airlines.

How can local governments possibly stand with airlines as equal participants when the government bears all long-term risk and the airline can leave at will, abrogating their contracts through creative restructuring every few years? It's not possible; it's a dysfunctional alignment what we have established with our own legislation.

It's as if the military were to adopt a terminal leave policy of: you can leave whenever you want. We'll try to accomplish the Mission without you.

Sometimes we recognize negative trends in time to be able to understand that we've been screwed, but the emotional time-latency and arrested focus on the last time can keep us from seeing how today's rent-seeking works.

Sure, airlines have taken what we gave them - deregulation - and reverted to type. Let's not cry too much about the past, let's look at what's now. Accomplishing the American Aerotropolis and ensuring successful cities in an environment of global competition requires a regulated airline industry.

Don't even start with Spaceports. Please.
November 03, 2009

New Airline / Flight School In Pittsburgh

The Post Gazette brings us the story of Gulfstream International Airlines, which may reintroduce air service from PIT to Harrisburg, DuBois, Cleveland, Indianapolis, and other smallish cities. They're going to fly 19-seat Beechcraft 1900's, which are really nice airplanes.

No less a person than County Executive Dan Onorato said, "We are thrilled that Gulfstream International Airlines is interested in restoring important regional flights to our world-class airport".

On the face of it, it's more good news. It's evident that people are working hard to attract new airline service, and I applaud that. For instance, the recent incentivized/ guaranteed service to Paris, France with Delta - that was a great move.

The thing is: We know Delta Airlines.
We've flown Delta Airlines.
This Gulfstream Int'l outfit is no Delta Airlines.

Gulfstream flies as a Continental Connection carrier. You remember Continental Connection, the umbrella outfit that outsources airline passengers to low-cost contractors, like Continental Connection Flight 3407 which crashed while approaching Buffalo Niagara International Airport recently. The passenger's tickets said Continental, but the airplane and crew were Colgan Air.

From Wikipedia:
Gulfstream International Airlines has been under additional scrutiny due to three recent fatal crashes that all involved pilots that were trained at the Gulfstream Training Academy (its sister company), the last one in February 2009, where 50 died on Colgan Air Flight 3407 near Buffalo, NY.

In May 2009, the federal government issued a fine of 1.3 million dollars against Gulfstream International Airlines after the Federal Aviation Administration found that it had falsified flight time records, allowing crews fly longer hours than allowed by law, and providing below standard aircraft maintenance. The fine is being disputed at this time.
  • In July 1997, the airline's entire fleet of Shorts 360-300s were repossessed by the leasing company due, in part, to maintenance irregularities that included the welding of hydraulic lines
  • Despite its status as a mere stepping stone in the minds of most pilot employees, the company was able to keep whistle blowing in check through selective disclosure of training documents

It's not just an airline, it's an adventure


Gulfstream is not just an airline; it's a flight school. The Gulfstream Training Academy (check the site, very TopGun) teache$ people to be pilots. It's a flight school. Then the graduates can pay to be copilots on your Continental Connection flight! They pay tens of thousands of dollars, get 250 hours of experience as a copilot, and the airline pays them $8 an hour. They are, essentially, taking lessons with uninformed passengers in the back.

Here's the menu: for $25K they'll declare you a co-pilot (aka first officer) in three months; for $48K they'll declare you a pilot in five months. If you don't have any flying experience at all, for $73K they'll make you all that in 14 months. The brochure calls the time you spend flying around (pretending to be a copilot) the "first officer internship". George Orwell would be proud.

Your family sitting in the back of the Beech 1900? Priceless.

It's really a brilliant "business model". In addition to charging passengers for snacks, drinks, headsets, blankets, and checked baggage - hey, let's charge somebody who wants to learn to be a copilot, and let them ride up front!

From USA Today:
Capt. Marvin Renslow, who was at the controls when a Colgan Air commuter plane went wildly out of control and plunged to the ground on Feb. 12, trained with Gulfstream in 2004 and 2005, according to National Transportation Safety Board records. Colgan Air was operating under contract for Continental Airlines at the time of the Buffalo crash.

The copilot on a Comair flight that crashed in 2006 after trying to take off from a dark, closed runway in Lexington, killing 49 of 50 people aboard, also worked at Gulfstream, according to NTSB records. So did the two pilots on a Pinnacle Airlines flight who were joyriding in an empty jet before snuffing out both engines and crashing in Missouri in 2004.

I really do applaud the people trying to rebuild air service. But I've got a message for Dan Onorato: you'd be better off with MagLev. Or Greyhound. Or anybody where the co-pilot isn't an intern, paying for the experience.



Related Posts: 30 Years of Outsourcing Safety.
August 06, 2009

Eliminating Most Airline / Airport Delays



How can we prevent airline delays and airport delays across the nation? I can tell you how to do it, but to be fair I must say that this solution will be politically unpopular because it cramps the chosen status quo of airports and airlines. Passengers, however, will love this. There's both an engineering factor and a policy factor.

Before I get all lofty and theoretical, I'd like to share a phrase that I learned a long time ago: you can't put ten pounds of $h17 in a five-pound-bag. The basis of this approach is to recognize our five-pound bags, and adjust accordingly.

Engineering Factors in Eliminating Airline Delays

We need to limit scheduled airline traffic so that it does not exceed the known hourly capacity of both the arrival and departure airports.
That's a simple sentence that, in fairness, requires some exploration for details.

"known hourly capacity"
Every major airport has a chart that shows the airport capacity in terms of the number of arrivals and departures per hour, in "visual" (great) weather, in marginal weather, and in instrument conditions (bad weather). These airport capacity charts may also vary by the prevailing wind, which affects runway selection decisions. Airport capacity values are generated by the FAA.

Here is a basic airport capacity chart for EWR, LGA, and JFK.
Airport Capacity in (Arrivals+Departures)/Hour, by Type and (Freq) of Weather
JFKiEWRiLGAi
Visual (Great) Weather81, (86%)88, (82%)82, (81%)
Marginal Weather81, (5%)80, (9%)79, (10%)
Instrument (Bad) Weather65, (9%)64, (9%)72, (9%)

If you wanted to avoid all delays, you would set the airport capacity at the lowest of the three rates, using the instrument weather rates. If some delays were acceptable, you could set the airport capacity at the marginal weather rates.

If we required that airline schedules could not exceed the airport capacity at departure and destination airports, we would eliminate most airline/ airport delays. The remaining delays would be due to snow/ice storms.

"limit scheduled airline traffic"
It's a simple thing to say that if the hourly capacity is 70 airplanes, then the airlines shouldn't schedule more than 70. The implementation is much more complex. Some airlines are competitors. Coordination between airlines can be monopolistic. One approach to allocating limited resources (slots per hour) is to conduct an auction, allowing market forces to determine the value of the slots.

Policy Options in Eliminating Airport Delays

So we've decided that the Metroville Airport has a capacity of 70 airliners an hour. How do we decide which 70 airliners get to come and go?

One approach is for the Federal government to conduct an auction of slots. While economists tend to love this approach, local government resents Big Uncle Sam choosing their airlines. I'd like to point out a few things:
Who builds airports? Local government, usually a County or Authority.
Who owns airports? Local government.
Who manages airports? Local government.
Can an airline fly into an airport without gate/ramp space? No.
Who sells the airlines gate/ramp space? Local government.
Who profits from the airport? Local government.

I think local government, the Port Authority, should allocate their airport's slots. If they want to give the majority to Delta, that's great. If they want to sell to the highest bidder -- that's great, too. The revenues from selling those slots should go to the Port Authority. It's their airport.

Finally, every new paradigm must have an incentive-enforcement mechanism, or else it's a paper tiger. Any airport that allows an airline schedule that exceeds airport capacity pays a $5,000 penalty per airplane, per day. Any airline that exceeds airport capacity pays a $5,000 penalty per airplane, per day. This will make them very interested in honoring the capacity limits. They're going to start caring about delays, because we're moving some costs from the passengers to the airline/airport.

Other Than Snow and Ice, You May Never Be Delayed Again

Airlines will want to sell the same number of tickets that they did pre-constraint. They'll introduce larger aircraft into their fleet mix, so they can carry the same number of people in fewer airplanes. Industry emphasis will shift from numbers of flights to numbers of people, which is closer to the ideal parameter.

The cashflow of giving the Port Authority the revenue from any slots auctions, or allowing them to integrate slots into their business arrangements with the airlines, should provide sufficient inducement to change the status quo.

To summarize: We can eliminate most airline and airport delays with these steps:
  • Airline schedules must fit within (departure and destination) airport capacity.
  • Airport capacity is set as a federal standard.
  • The Port Authority or Airport Authority allocates their slots at their airport, within the Fed standard. Revenues go to the Port Authority.
  • $5000 penalty for scheduling over capacity for both airport and airline, per plane per day.

This will eliminate most airline and airport delays.

Tomorrow, we'll provide an additional solution to delays at JFK, EWR, and LGA. This additional innovation will eliminate delays (except for snow, ice, and T-storms) at JFK, EWR, and LGA for $15 million over five years.

If you want to send me 10% of that amount, that's fine, but it's not necessary.

July 07, 2009

Solving the ATC Delay Problem




I am not a good writer, and I am certainly not a brief writer, but I believe that accuracy in naming and describing things is to be desired, and I am enough of a fan of George Orwell to believe that correcting a misleading phrase is a public service.

Recalibrating the Frame

So I must ask that we reconsider the frame suggested by the often used phrase, ATC Delays. In general, ATC does not delay aircraft; ATC just tries to keep them from hitting each other.

Weather is a primary cause of airplane delays. When the weather is bad and unsafe, planes wait on the ground. Don't you think this is wise? Not too many passengers are willing to say, Damn the weather! Tell that pilot to takeoff anyway!

Airline Schedules delay airplanes, which is a paradox of sorts. Usually, schedules keep things on time. (They may complain publicly, but watch what they do, not what they say.) When airlines schedule more departures in a given time than the airport can provide for, then the airport is overloaded and the schedule has caused a delay. The crew may tell the people in the back that "we've got an ATC delay for Boston", but it's probably a scheduled delay that somebody in the airline intentionally designed.

Delays are often an act of commission; the airline industry has clearly found delays to be cost effective over time. This is an external diseconomy: the cost of delays are borne by the public, and the profits of overscheduling accrue to the airlines.

I would like to change the title of this piece (and the public discourse) to,

Solving the ATC Delay Airline Scheduling Problem

Imagine if the railroads scheduled more trains than they had tracks for. Imagine if restaurants scheduled more reservations than they have tables for. And yet, we consider it acceptable for an airline to promise people that 23 jets will arrive in 15 minutes at an airport that, in perfect conditions, can only get 15 down.

Perhaps it shouldn't surprise anybody that the same industry sells 110 seats on a 105-seat aircraft, because they choose to "overbook" as a matter of policy.


Tragedy of the Commons

From economics we have the Tragedy of the Commons (by Garrett Hardin) which is what happens when a common, unregulated resource is overused by people acting in their own best interest. In its most simple expression, the Commons is a large field in the center of town. People let their cows graze on it.

It is in each herder's interest to put as many cows as possible onto the land, even if the commons are damaged as a result. The herder receives all of the benefits from the additional cows, while the damage to the commons is shared by the entire group. If all herders make this individually rational decision, however, the commons are destroyed and all herders suffer. This was literally the experience at Boston Common, but the phrase itself is extended to larger concepts.

I'm sorry to repeat myself, but if those herders had adhered to Kant's Categorical Imperative (only do something if it's okay for everybody to do it) there'd be no problem. If airline schedulers listened to Kant, then airports would be all right, too.

Clarifying the Commons

Let's clarify a few relationships, in the hope of avoiding confusion later.
Who builds airports? Local government, usually a County or Authority.
Who owns airports? Local government.
Who manages airports? Local government.
Can an airline fly into an airport without gate/ramp space? No.
Who sells the airlines gate/ramp space? Local government.
Who profits from the airport? Local government.
Who pays for 90% of the airport? Federal government.
Who works the airline's planes through the local gov't's airport? Federal gov't.
Does the federal government have influence over airline schedules? No.
Who gets blamed for airport congestion? Federal government.

You couldn't make this up, nobody would believe it. I'm open to correction, but it seems like the Feds get the blame for a situation they didn't create and don't have any authority over.

Protecting the Commons

In general, the response to abuse of the Commons is to regulate the commons. In fact, some economists believe that the phrase should be changed to, Tragedy of the Unregulated Commons. Hardin himself concurs with the revision.

So, to follow my points (if I have made any),
  • Runways are constraints
  • Constraints must be addressed
  • An unregulated commons extends benefits to the abusers
    and extends costs to the community

Let us consider what Regulation might bring, and see if it is more or less onerous than current conditions.

Airport Capacity

We have talked of runways and runway capacity, but we should really talk about Airports because that's where people go to fly. An airport is generally a collection of several runways. The configuration of those runways will lead to an "Airport Capacity", and variations in configuration lead to variations in airport capacity. For instance, an airport with widely spaced parallel runways can conduct independent operations even in low weather, but an airport with intersecting runways must run interdependent operations in nice weather, and may have conflicts between the runways in bad weather.

Here is a chart of airport capacity at PHL, EWR, LGA, and JFK.
Airport Capacity in (Arrivals+Departures)/Hour, by Type and (Freq) of Weather
PHLiJFKiEWRiLGAi
Optimal Weather110, (86%)81, (86%)88, (82%)82, (81%)
Marginal Weather99, (6%)81, (5%)80, (9%)79, (10%)
IFR Weather96, (8%)65, (9%)64, (9%)72, (9%)


As you can see, the airports have their highest capacity in optimal weather conditions, a reduced capacity in marginal conditions, and their lowest capacity in instrument conditions.

Which Capacity Should We Use To Regulate?

So we have three numbers for airport capacity/hour at PHL - 110 in optimal weather, 99 in marginal weather, 96 in instrument weather. Which value should be used to regulate the volume of airplanes?

WWED : What would an Engineer Do?

An engineer would probably pick the instrument capability as the constraining value, which would ensure a flow of traffic that was always within the capability of the airport. In response to questions about unused capacity during nice weather, the engineer would say (1) we don't design systems for optimal conditions, and (2) the unused capacity on nice days leaves room for unscheduled general aviation and charter flights.

WWGD : What would Goldilocks Do?

Goldilocks would avoid the extremes and take the middle choice, echoing Aristotle's Golden Mean. Goldilocks would pick the Marginal Weather Capability value.

WWVD : What would Vannevar Do?

I'd pick an airport capacity that would accomodate operations 95% of the time, generating delays only 5% of the time. This 95th percentile capacity value would result in airport capacity values of PHL: 98/hour, JFK: 73/hour, EWR: 72/hour, LGA: 75/hour.

WWSD: What would Solomon Do?

Solomon, known for his wisdom and pragmatism, would probably say: Adopting any of these values as the hourly capacity for the airport, and enforcing that limit, is so much improved over the chaotic status quo that any of them is acceptable.

How would you administer the limit?

There are multiple options available for administering the limit. Options include:

The Lottery

Usually, lotteries are appropriate to randomize the delivery of windfalls and tragedies. Who wins a million? Who gets drafted? A lottery would have a randomly distributed result, but probably not an effective result. If airlines were permitted to buy and swap slots, this would truly be gambling over public assets.

Federally Reregulated Airlines

Airline deregulation in 1978 caused a fair amount of this problem, although congested airports existed during deregulation. The federal government could regulate airlines on a national level, distributing slots per hour at the 35 major airports (the OEP airports).

Locally Regulated Airports

Federal government sets the hourly capability for the airport based on technical factors, and then the Feds are out of it. Airports will be responsible for assigning their available slots as they see fit. They may choose between arrivals and departures; they may choose among airlines. Local airport boards, who have control over airport construction and management, and who enter into airline leases for gate and terminal space, will be able to coordinate their airline activity as they see fit within federal capacity standards. Airports will not be allowed to tolerate airline schedules over and above their capability, on pain of losing their AIP (Airport Improvement Program) largess.

How do the Airlines Respond?

So now the airlines are regulated and restricted to a certain number of takeoffs and landings per hour. Those operations can be assigned by (1) lottery, (2) federal planning, (3) local airport preference/auction.

Last year, the airlines routinely scheduled 80 operations per hour.
Next year, the airlines are only authorized 60 operations per hour.
How do the airlines respond?

Airlines will respond rationally

If you give an airline 6 operations/hour rather than 8, they'll optimize their business to make profits within the new structure. Instead of twelve departures/day from LGA to Richmond, VA, maybe they'll have five and fill every seat. They may start flying 128-to-159-seat Boeing Classic 737s instead of 50-to-100-seat Regional Jets. (They started flying the RJ's for union busting anyway, not their operating costs.)

The focus will go from airplanes to people

Really, nobody should care about airplanes; we should care about people. When we reduce Newark to 72 operations/hour, and Continental thinks it can sell the same number of tickets, they'll schedule bigger airplanes. The result? Same number of passengers moving, fewer aircraft, fewer people delayed.

This shift to people-focus is complex. For instance, if Continental decided to use B767s instead of B737s, the B767 will need additional wake turbulence spacing, and it becomes a multivariable problem. They have lots of computers, they'll figure it out.


The airlines and the airports have been overbooking the runways just like the airlines overbook seats on their planes. They do it because it's cost-effective; the profits go to the airlines and airports, and the costs go to the travelling public and the economy. When too many show up, they bump some back to the next hour, and so on, and so on.

What Won't Solve the Airline Scheduling Problem

Flow Control

For at least twenty years, Flow Control has attempted to stand between the unrestricted, uncoordinated airline schedule and the known capacity of airports. Perversely, federal Flow Control imposes delays on a situation they did not design and have no authority over, to keep the operational situation from snowballing into ramp gridlock and unsafe situations. We throw more money and attention into Flow Control each year, and it has not improved the situation since at least 1985. We should abandon this flawed concept and deal with the root issue.

NextGen

The current aviation system can deliver any number of aircraft you'd like to the airport. What would you like - 40/hour, 80/hour, 120/hour, 180/hour? The "outdated WW2 system" can do that now. The constraint is the runways, and NextGen will not do anything about runways.

Look at the 9/11 grounding of all airborne aircraft, an unprecedented feat of choreography. The legacy system and the people at the scopes made it look easy. NextGen would not have passed the 9/11 test.

Vannevar's Recommendation

  • Calculate hourly airport capacity based on 95th-percentile weather conditions.
  • Manage the constraint with Locally Regulated Airports. Let the people who own the airport, who profit from the airport, and who rent space to the airlines manage their own capacity as they see fit. Take AIP funds away from those that don't.
  • Incentivize desired behavior. Any person delayed more than 20 minutes should get a $100 cash payment from the airline. Any person delayed more than 40 minutes should get a $200 cash payment from the airline. When delay costs become internal rather than external, those smart airline guys will become concerned about delays.
Until we identify, quantify, and manage constraints, the Airports and Airlines deserve the delays that they're designing. The costs are born by the public, and the benefits go to the Airports and Airlines.




Don Brown, a highly respected, thoughtful guy with an operational perspective, presented his recommendations in Sept. 2007.






Overton Window Alert: On the web today, 7/7/09: The United States... ...has adopted a pragmatic approach to the future of its national airspace system, based on a desired mid-term outcome that makes the best of technologies already available and gives industry a leading role in showing the way forward....


October 10, 2001

2009 Airline - Airport Delays Series


  1. August is National Trapped on the Tarmac Month

  2. Airport Delays and Capacity : Runways vs NextGen at JFK

  3. Why are airport / airline delays the same, year after year?

  4. Eliminating Most Airline and Airport Delays

  5. Priorities and Connections : Eliminating Airline - Airport Delays