Keeping size limitations in mind, PSP-like thumbslider 2-axis controllers will feature in this project. The low-profile will help this controller fit in your pocket.

2 momentary and 2 latching buttons will enable the activation of different flight modes and programs.

The integrating 'brain' of this project will be the Arduino Nano, or possibly the Mini if the Nano lacks any processing power. It will translate the input from the controls and output PWM signals that can be transmitted via wireless communication channel(s).