Keep looking! By now, the rx battery is most likely dead, so the servos won't be working anymore. Get a helper. Stand where you were standing when it went in, and direct your helper to the general area. Lots of times, we begin looking in the wrong place because we get disoriented on where we think it went down. Don't overlook the possibility that it might have fallen to the ground, so look everywhere. You might even get a BIG spotlight, go out at dusk or dawn, when the sun isn't as bright, and start pointing that bright light up in the trees. The spotlight might reflect off of the covering and catch your attention--like a mirror of sorts. During the day, the sun would be doing this, but from above--no help to you. Just some thoughts.