Another article in Slate about airport delays, written by a economics professor. He thinks its due to the fact that major carriers use a hub and spoke business model, that is, all their flights connect at Chicago O'Hare. One problem is that all these carriers schedule huge batches of flights at once, between 10-20, at peak times of the day. Such an overload by itself drowns the system because air traffic control can't let planes take off so quickly (another issue is wake turbulence, generated by aircraft while taking off, which causes aircraft behind them to get caught in unstable wind vortexes).

The hub-and-spoke model is in contrast to low-cost air carriers such as southwest, who mostly do point to point operations, no transfers involved. Since all their flights are regional, they don't overwelm one major airport with massive amounts of takeoffs and landings. But southwest also has flight delay issues too. From the FAA, in May 2005, Continental was on time 83% of the time, while SW was on time 86% of the time. But, if you look into the details (available at the FAA website here) you'll see that while Continental had 9.5% of flights delayed due to 'national aviation system delay', only 2.25% of SW flights are delayed due to that. So basically the theory holds, using these two carriers as models. My wife likes to travel SW for the convenience factor, but I trust Continental more.

Anyway here are some tips to avoid airport delay.

1) If you are using a major carrier (ie Continental) in a hub (ie Houston, Chicago), find off-peak flights if possible; look at all their flights leaving that day from that location, and find the one with the most time before and after that flight, ie pick a flight that leaves at 8am, since only 5 flights are leaving at 8am, vs 9am where 10 flights are leaving.

2) Book an early flight which originates locally (not always applicable to everyone. But most all of Continental's early morning flights originate from Houston, so there is no dependance on waiting for an aircraft to show up.

3) Book a regional carrier from a smaller airport. On the other hand, if there is a problem with one aircraft, then it will be harder to find other aircraft to 'take up the slack'.

I still prefer taking my chances with a big carrier; I've never had a problem with Continental yet. Several times my wife and I were stuck at thankgiving waiting for a SW flight to show up.