The logistics and industrial base to keep airplanes going is insane. They would have an Air Force but it would not last too long as spare parts dry up. Remember the industrial base is spread out across the country (much in red states) mainly defense lobbyists getting congress votes reasons. But that makes it ridiculously inefficient and why the high tech weapons cost so damn much. But in a SHTF scenario it would become not only inefficient but completely dysfunctional.