The next two incarnations of Air Force 1 (based on the 747-8) are now supposed to be delivered in the 2026-2028 time frame, several years late. Boeing says that it was a "mistake" to accept the $3.9 billion contract because of cost over runs. You'd expect these aircraft to stay in service for a decade or more, but with 747 production ending, I wonder if spare parts will become a concern somewhere down the line. (There's probably a clause in the contracts somewhere about future spare part availability.)
