[douglas]

The unit limit only applies to units in space. Units in cargo, such as troops on a planet, do not count towards that total. Minefields, deployed satellites, launched drones, and fighters launched outside of combat or with no carrier to return to at the end of combat do count towards that limit, but any and all units that are in cargo are exempt. You could have several billion troops in your empire and it wouldn't matter at all as far as the unit limit goes.