I know this was suggested before this is just my aproach of the idea!
This feature was last seen in Chicken invaders 4 in one single mission where you had Hen Solo helping you, we haven’t seen this happen ever again. So I wanted to suggest this thing where you coukd equip various helpful spaceships to fly with you in a mission.
There would be new slots on spaceship configuration screen. Bellow hardpoints there would be a new “assist wingman” slots, H&C spaceships would have only one slot, M404 ships would have 2 and bombers would have 3 slots. You could buy and equip multiple of same spaceships if you want and customize them. Here’s the screenshot: