The United States Air Force (USAF) doesn't have "snipers." The USAF trains their members in a Countersniper school. They aren't trained in the same tactical employment role as the Army snipers or the Marine MOS snipers.
The initial course which snipers go through to be selected as snipers is longer in the Marines. However, once selected, training is going to be intensive for snipers in both branches, and they'll end up being on par with each other.