Hi,
Heres the question.

1. Can a flyer attack another flyer with ranged powers if they are based by each other.

Not anymore, no.

No because if it did fliers would automatically have the sharp shooter ability as well... Thats my take on it.

Fliers used to be able to shoot and be shot at by adjacent characters, but that rule was removed--around the time of Legion of Super Heroes or Fantastic Four starters, I think.