It survived. It kept recording. Luckily, friendly people doing gardening found it lying in their yard. After checking that it was not their phone, they eventually contacted the owner and returned it. Well done!
Filming with your cell phone from the open window of a small airplane apparently is risky as this owner found out when his Samsung Galaxy S5 got sucked out of his hands and hurtled 1000 feet to the ground. In the picture above, you can see the plane at the bottom as the phone tumbles toward the ground.