Wouldn't this be a great place for a failsafe command set?
The code linked in reply 8 above should do what you want. Each channel can be individually set to a user defined failsafe value which will be returned on detection of loss of a valid signal. (Alternatively, any channel can be set to use the last good value received.)
The fail-safe could trigger an autopilot in a plane, but simpler is to just idle the motor and set the controls for a gentle turn so hopefully the plane will circle, gliding down to land somewhere near the pilot.
I am trying to find some time to do write-up on this library for the playground. Hopefully I will get to it this weekend, but the most recent code posted at the end of the thread does have that fails-safe capability.