If you are using a typical 72 MHz transmitter, the signal can travel over 1 mile and perhaps as far as 2 mile. That means that you can shoot down another plane with about a 6 square mile area. You may think you are flying alone but in fact you could be mesing with someone else's plane or they could be shooting you down.

If you want to fly "off field" you sould get a 2.4 GHz transmitter.