Apparently the good ones can be programmed with a homing type setting so that if things go wrong it flies itself to somewhere you want. My mate bought a second hand expensive one for £400. He didn’t set this. He flew it the very first time, next to Hatchmere, and it had already been set by the previous owner, he pressed the wrong button and it sailed off over the trees never to be seen again. He literally got less than a minute from it. It still makes me laugh. He used to go out searching for it in the direction it flew every weekend.