Controlling UAV in FBWA mode

Hello everyone, first of all, thank you for your attention. I have some questions about controlling a UAV in FBWA mode.

First, I would like to know if it is possible to control the UAV without GPS. If so, is there a way to control it? Could you explain how, in short?

Then, I would like to know if an airspeed sensor is required when controlling the UAV without GPS.

Arduplane requires either GPS or Airspeed sensor to work.