I agree. Fear of heights is a very common problem. You have already prove to yourself that you can fly without it being in your way and the rest is about building your confidence as you fly further and higher. The worse you can do is to get stuck around a specific area of heights or flying and then believe you can't get past it. Feelings are just feelings and are constantly changing. However, if you do get stuck and it becomes a panic state, don't worry as you can get help for that. But, so far, in your case, you doing well and just keep doing it!
Good luck
FS