If you used two transmitters, one on the ground and one in the air, you could get both model and full-size aircraft airborne, then either with a prearranged light signal or by radio, hand control over by simultaneous switching off/on the transmitters using a countdown.
Flying opposite hand circuits with an agreed 'glass wall' so that the airborne pilot can take over when the model is ahead and to one side of the model at handover would help. As with 'buddy box' flying it is important that trim and throttle positions are all confirmed so nothing sudden happens on hand over.
The full-size pilot should be flying a pre-agreed circuit once hand over is complete, and it should obviously be over open countryside (preferably empty farmland or water).
Allow plenty of time well in advance to cover all the possible things that might go wrong with either aircraft, comms, unexpected traffic, you name it. You don't want to have to be making decisions on the hoof. The full-size pilot should just fly a nice steady pattern. Chasing the model around the sky shouldn't be an option.
For the full-size aircraft I would have thought a microlight trike would give much better visibility than a Cub. You have to remember that the full-size pilot won't be able to concentrate on keeping the model in sight, so what do you do if it goes in a blind spot? First person video would at least let you see the full-size aircraft from the model, even if you can't see it.
As has been mentioned, models have been flown from helicopters, and I should think it has been done for filmwork as well. The secret is in the planning. How about seeing if you can control an R/C buggy from the air when the wind is blowing down the strip, and how long you can keep an R/C slope soarer or even your F-16 'foamie' hovering within a frame to one side of you when standing on a hill in a good wind?
Finally, can it all be done with the approval of the CAA and within the terms of the aircraft's insurance? Evidence of planning, risk assessments and relevant experience count far more than 'Hey y'all watch this'.
Last edited by Mechta; 28th May 2011 at 22:54.