BIND-AND-FLY!
In the Tiny Whoop world, BNF is short for Bind-And-Fly. We inherited this term from the greater RC community, and it pretty much just means one complete pre-built aircraft with all necessary parts (including the receiver) installed. Just bind it to your tx and fly!
BNF aircraft do not include a Remote Controller (transmitter) nor goggles, and usually to not include a battery for the aircraft.