Is your Transmitter on PCM and your plane not? I switch back and forth with a Heli that is set up on PCM and my planes are PPM. When switching you have to cycle power to the transmitter for it to take. I have been doing this all season and just last week my plane got the jitters. Took me by surprise for a moment and then it became obvious to me what was going on. Brain fade for amoment I guess.
Just a thought,
Peter