how to detecting the bluetooth connect or not?

I am using the arduino pro mini to make a bluetooth airplane. But I'm so worry about if the bluetooth not connect how can I know?And how to make it stop?

I think you are getting panicky. Most bluetooth modules give a clear indication that they are connected. All you need do is ensure that it is before takeoff. If you really want it to stop, you turn off the connection at the controller. The only other problem is to ensure the aeroplane stays in bluetooth range. If you don't, the connection will stop by itself.

en6robot: And how to make it stop?