What happens to all of those airplanes built for war in times a relative peace? Well, they get mothballed for future conflicts in places called “boneyards“. The largest aircraft boneyard in the United States is the one in Tucson, Arizona.
The official name of the boneyard is the 309th Aerospace Maintenance and Regeneration Group (AMARG) This is an United States Air Force aircraft and missile storage and maintenance facility in Tucson, Arizona, located on Davis–Monthan Air Force Base. It was established after World War II to mothball excess airplanes and now takes care of nearly 4,000 aircraft. It is the largest aircraft storage and preservation facility in the world.
You can sign up for tours of the boneyard through the Pima Air & Space Museum although you need to make reservations well in advance because you need to apply for a security clearance pass.