It had never occurred to me before reading this FC Experts post, but the poster may very well be right that "There's no future in flight if planes have no place to park." From the post:
Yet that's exactly the future we face, with 14 U.S. airports and eight metropolitan areas needing new capacity to accommodate anticipated growth in air traffic through 2025. In fact, 15 metro areas will not be able to manage demand by 2025 unless they act now. Places like New York City, Boston, and Los Angeles need to identify better ways to use existing, smaller, or underused airports â€” and they need to do it fast.