You must have a save file anytime after you begin Hell mode. You can verify this by going to the load screen and it will tell you which mode your save file is for, ie, beginner, expert or hell. You need to have Hell mode as current. Load the profile. Now, rename the save file. It will automatically save. You can now continue Hell mode and you will get to choose your aircraft type. You will get all rewards and achievements as if you were only using the F1 aircraft.