Whats the difference between the Development Board and the Flight Module?
The Development Board is on a much larger PCB to facilitate access to the various systems on-board. It also includes provisions for multiple power supply sources, and jumpers to isolate parts on the system. It also includes some additional circuitry not available on the Flight Module (e.g. +5V and +3.3V regulators, indicator LEDs, and an RS-232 port). Electrically, the Flight Module is a subset of the Development Board.