The Troop Transport Unit module allows a unit to transport other units by land, sea, or air, depending on the unit's chassis.
Only sea-faring units can transport more than one unit at a time. A Foil can transport a number of units equal to twice its reactor value. A Cruiser can transport a number of units equal to four times its reactor value.
Transports can normally transport only ground units, but sea-faring transports can be given the Carrier Deck special ability to allow them to transport and refuel air units.