I don' think there are any major warbirds museums around Vegas, There's some neat aviation displays at the airport. Nellis AFB has a small museum, you probably have to find out where and when you could access the base. If you're there around a weekend you could try Henderson or North Las Vegas airports. Sometimes some warbirds go into each airport.
Howdy , absolutely the best aviation museum in the US is The United States Airforce Museum in Dayton, Ohio. If you are going to be that close don't miss it. I saw an SR 71 BlackBird there 35 years ago . At the time it was still classified and top secret.