If they were stupid enough to leave them in hangars and HAZ, relatively simple. A US general said this morning that if ordered they could take out every base in a day.
However, runways are easy to repair; and as found in GWI HAZ can be filled with rags and oil to make it look like an aircraft was inside/destroyed. The real things can be towed off base and put beside hospitals or hidden inside factories etc and towed back for take-off or launched from roads.
The figures for the number of aircraft required in GWI to be required to go back day after day to make sure a large dessert base with multiple runways stayed shut was eye opening.