which IMAX? Udvar-Hazy or an equivalent?
You might want to consider going to Pensacola FL in the spring when they are practicing multiple times per week. We took the kids a few years ago for spring break and saw them practice twice, once from a boat directly underneath their flight path. The other time was from the naval aviation museum grounds. We also saw the French equivalent to the Thunderbirds who were in town that week to prep for a joint show. About 10 years ago I was able to get into the VIP area to watch them perform at Andrews during the big air show. I was about 20' from the narrator, hanging out with the families on the front of the flight line.