I would put more time into finding the cause than just looking up and saying "he did it" to the plane flying over head. There is no way possible that the full scale plane caused your crash unless you were watching him instead of flying your plane and just lost control. I would bet your RX pack was weak, and built up enough after it hit the tree and you turned it off to move the controls again. I would check the radio out good and make sure the switch is good, (read that replace the switch, its cheap) and cycle the battery and find out how long you can actually fly. If you had a servo hanging up, it could have dropped the battery enough to kill the power, and then it could build back up in the time you walked it back to the car.

Don't just blame something handy, find the real problem, or you will lose another for the same reason.