Can a doctor become a jet fighter pilot?

Sure, why not? The only problem is that at some point, age becomes a factor. When you say "jet fighter pilot" you're really talking about a military pilot, and the military generally stops accepting officer (pilot) candidates at around age 26. Because of the educational requirements, there are probably not too many doctors who have finished their training that are 26 or younger...but it's certainly possible. There are waivers granted under certain conditions, but those are granted on a case-by-case basis. Another thought would be to consider being a Flight Surgeon. These are doctors specializing in aviation physiology and in the Navy, at least, they have the opportunity to learn to fly and solo as part of their training. Flight Surgeons are accepted into the program at ages above age 26. For more information, see your Navy or Air force recruiter...and if you're really interested, you better get cracking. Good luck.