I recall going to one near Galveston in Texas which was good. I have been to the Evergreen museum with the Spruce goose. If its any use even my ex wife commented that it was interesting and one of the better ones we had visited.
Pima and the Boneyard are a must, San Diego is also good and obviously the Smithsonian goes without saying.
Personally I was recentally in Savannah where there is a museum dedicated to the 8th Air Force. A B47 and B17 etc however the sheer amount of history, memorabilia and dedication to those who served in the East of England was simply fascinating. I bitterly regret not allocating more time to it as it was simply one of the most interesting museums I have been to.