If you have the opportunity, a stop at the National Museum of the United States Air Force in Dayton, Ohio, is a great way to spend an afternoon.  And it’s absolutely free!  Even if you think that military history really isn’t your thing, this place is worth a stop.  The exhibits here are pretty awe-inspiring. The buildings that house the museum are impressive in themselves.  The main building tells you that you are about to see some big planes. The National Museum of the USAF, located at the Wright-Patterson Air Force Base, is the official museum of the Air Force.  Although the museum is free, be prepared to go through security.   Since we were on a road trip and our time was limited, we made a brief stop and were determined to see the highlights.  The museum is open 9:00 a.m. until 5:00 p.m., so try to give yourself…