Why am I always stuck at O'Hare?
From The Slate's Austin Goolsbee:
Mayer and Sinai's study also identified the real culprit: the deliberate overscheduling of flights at peak periods by major airlines trying to increase the amount of connecting traffic at their hub airports. Major airlines like United, Delta, and American use a hub-and-spoke model as a way to offer consumers more flight choices and to save money by centralizing operations. Most of the traffic they send through a hub is on the way to somewhere else. (Low-cost carriers, on the other hand, typically carry passengers from one point to another without offering many connections.) Overscheduling at the hubs can't explain all delays—weather and maintenance problems also contribute. But nationally, about 75 percent of flights go in or out of hub airports, making overscheduling the most important factor.
American Airlines, for example, uses O'Hare as a hub and schedules a cluster of flights to arrive there from the east in the earlier afternoon. Another cluster leaves for points west and south soon after. In the 30-minute period between 2:45 p.m. and 3:15 p.m., American has scheduled about 18 takeoffs, not counting its regional flights. That comes close to maxing out the airport's capacity, without any other airline. Other airports are even more extreme. Continental has seven flights scheduled to depart during the exact same minute (11:45 a.m.) out of Newark, as well as almost 20 other flights in the surrounding half hour. Some of these flights leave late more than 80 percent of the time. The major airlines know perfectly well that these hideous statistics are inevitable.