G2 controller issues.
Interlink versions of RealFlight G2 will refuse to start if the Interlink controller is not connected.
Non-Interlink versions (RF Classic, Deluxe, and G2 published before Spring 2002) are all happy with any joystick/gamepad style controller. I've flown RF G2 with Logitech RumblePad, which has two analog sticks on it, just laike a regular 4-axes joystick.