The Rebels, Robots and Colonies of Man can build fighters in space by placing 5kt supplies, 3kt Tritanium and 2kt Molybdenum per fighter that they want to build on a ship with at least 1 fighter bay.
While Robots and Colonies of Man have a ship mission: Build Fighters in Space, the Rebels can just load the resources and build the fighters without the mission. The ship needs fuel onboard to perform the “build fighters” mission.
Beside the build fighters mission and the Rebel auto build, all 3 races can use the lfm friendly code. Ships with lfm set will automatically load the minerals and supplies and build as many fighters as possible, regardless of the ship’s mission.