[Suicide Junkie]

If the ground combat from the first one results in defeat for you, the second one will drop troops to try again, providing the turn count is still <30. This can result in losing a lot of troops because the planet kills them off in 2 stages instead of using 1 large invasion force.

Even in tactical combat, you cannot simultaneously drop troops from two transports.

If your forces manage to hold out for a stalemate, the second transport will be able to add reinforcements, and both Groups of troops will fight together against the surviving militia.
This rarely happens in the unmodded game.

If the planet is captured, I believe that any extra troop transports will drop their troops on the remaining planets/moons.

A heavily armored troop transport would be a good idea for attacking small colonies.
If the colony has little to no defenses, you can send the transport in while your main fleet takes on the heavily defended planets.

[ March 02, 2003, 16:45: Message edited by: Suicide Junkie ]