It can carry maximum of two units. It can carry two infantry, or one infantry and either an artillery or a tank with the infantry, and there maybe other combinations I’m not thinking of such as mechs and AAA guns that can be carried with an infantry.
Someone that has more experience can help me here.
I hope this helps you, some what. :-)
PS I guess I should ask, are you talking about the transport ships or planes?
Are you talking about Global 1936 or 1939, because if it involves one of these, it could make a difference, depending on which type of transport plane you have?