This doesn't mean that they let him do a lot of the stunt flying. In one month's time he probably learned how to take off and land, fly a simple course, maybe hover, and maybe auto rotate. But there's no way that he could have learned to fly at high speeds, fly low, and do all sorts of stunts and tricks that would take years to get good enough to do. This is probably what they're doing for Top Gun 2, except instead of taking off and landing he's probably learning how operate an F-18 on a very basic level in the air, turn left, turn right, go up, go down, etc. A modern jet fighter is magnitudes more complicated and sophisticated than a helicopter, not to mention many times more expensive. There's no way that the Navy is going to let him do anything remotely fancy behind the stick in the air.