Infinite flight in my opinion has a lot of great features, but I have one feature I suggest.
Planes that can go fast enough to take you to space, and maybe planes that can fly to the moon. It would be great to fly to space. One plane could be the “North American X-15”, and could be added with a “Boeing B-52” airplane which carries the rocket plane. Even though the X-15 is retired, it be great for users to fly to space.
I have more suggestions, but I will hold them until later.