Ok, this is going to sound pretty dumb, but I can't get more than one transport at a time to invade a planet. I've got 4 transports stacked adjacent to a planet, and all have movement. I can't seem to form a fleet with them (haven't done that before either), if I hit the create fleet button, it seems to create an empty fleet, but won't put any transports in it (it looks to me that w/ 12 logistics ability I ought to be able to put 2 of my transports together in a fleet.
Anyhow, if I select all 4 transports as a stacked group, and right click on the planet, the invasion dialog comes up 4 times, each time showing my troop strength as 1000 (I have 2 troop modules on ea. transport). So far, I've just cancelled out, cause I'd like to get this right on the first try - but is it truly meant to be that you can only attack with one transport at a time???