IAH feels the growth from Delta DFW hub shutdownThe Houston Business Journal has an article about soaring 20% passenger growth at IAH in March vs. March of 2004. The article doesn't give the reasons, but there are two big ones: Easter was in March this year, and SkyTeam partner Delta closed their DFW hub at the end of January. Delta connected 6.4 million passengers a year through DFW (in addition to 2.9m locals), and a whole lot of them are now choosing to connect through Houston on Continental rather than DFW on American. I imagine almost all of them live in the South and usually connect on Delta through Atlanta for most trips, but Houston is more convenient for western trips and still lets them earn Delta SkyMiles (and American doesn't). This extra demand, in turn, let's Continental offer more frequencies to more destinations, which is certainly a benefit to Houston.
If the growth holds up over the year, we have a shot at moving up in the rankings from the 10th busiest airport in the nation to 5th (after the big 4 of Atlanta, Chicago, DFW, and LAX), and from 18th to 9th in the world - depending on how fast everyone else grows. It'll probably be our peak global ranking and downhill from there - those Asian airports are growing faster than Houston grass during a rainy summer.