White Flysky FS-i6x with 1 AA battery?
Using a single 14500 lithium battery which is the same size as AA batteries but higher in voltage; I'm able to power up my remote control as a 3rd option (aside from 4 AA batteries or a 1S battery mod I also did last year---check my videos).
These 14500 are really cheap, got it for around $1, bought 3 as I needed a 12v source to test out my car accessory mods).
reAlesTekally 5!