Is it posible to use this without the Ground Pi? Can we send controls, encode and display video in a laptop for example?
You need a raspberry pi ground station in OpenHD 2.0, but in 2.1 you will be able to run the ground side from a laptop if you want to.
Can self done programs run in the Air Pi?
Technically yea you could but it would be a bit of an odd thing to do, as the whole idea is for you to have constant realtime communication from the ground station.
In OpenHD 2.0 you can connect to mavlink-router on the ground station (or from a hotspot device) and run Mavlink commands if you want to.
In OpenHD 2.1 you could connect to the Mavlink router on the air side as well.
Is it possible to use 2 cameras and stream 2 videos?
Yes, 2.0 is designed around the idea of a main raspberry pi camera and then a 2nd camera that can be basically anything, a FLIR thermal camera, an IP camera, etc. The setup is a little tricky but you can ask for help if you need to.
In 2.1 it will be automatic, just connect your cameras and they’ll work.
Is it possible to fly without the need of a normal RC radio?
Yes, you can connect something like a Taranis to the ground station via USB, or make your own custom joystick controls (we have Arduino designs for this, as well as complete all-in-one ground stations, see the custom section of this forum).