DEN is the largest commercial airport in the U.S. DFW is 2nd. PIT has quietly bought a lot of land in the past 20 years and is fairly big, but nothing compared to DEN. MCI was one of the biggest airports in the world in the early 70's, but now it's just slightly large.

Burbank's terminal is too close to the runway that it would not be allowed if it were new construction.