is it surprisingly important, will I use it a lot ingame? Or is it not too important? Because my current team doesnt have a Pokemon with fly. This is in White 2 btw.
Unless you want to walk in order to backtrack... it doesn't matter if you want to fly or not. But yes it can be very useful if you want to save a lot of time.
Hope I helped :)
Fly is a very useful HM to have, not exactly important, but useful. It can be used to backtrack very easily. It can be useful in late game when you are trying to beat the Elite 4 and need to train. I suggest that you have a Pokemon on your team that can learn Fly.
Hope I helped!