Update 1.5.0 of Sky Force Reloaded added prestige points (a kind of "achievement points" that you get for your accumulated totals of kills, rescues and other metrics). Get enough of these and they in turn start unlocking technicians, that grant you some benefit while playing, and can be swapped out at the start of the mission similar to how planes can be.
What are the various technicians that can be unlocked and what effects do they have?