You can't both disembark units and then embark nearby units together as part of the aircraft's own action. However, once landed the thunderhawk is a ground unit, and as a transport war engine it should be able to embark troops that move into base contact with it:
4.2.5 wrote:
Once landed, the aircraft is treated in all ways as a ground unit with a speed of 0
Further clarified by:
Official FAQ wrote:
Q: Can a unit that disembarked from a War Engine to take part in an Assault use its consolidation move to get back into the War Engine?
A: Yes it can. However, if it does so then the War Engine loses its own Consolidation move (and War Engine Transports may not make a Disengagement move at the end of the turn) as it has to wait around while the troops climb back on board. Note that the War Engine may make a Consolidation move (or a Disengagement move if it is an aircraft) if no troops embark upon it.
So, the rulebook states that the landed aircraft becomes a regular war engine transport ground unit. The FAQ is about such war engines generally, but also refers to aircraft disengagement moves specifically. The implication is that you
can move into the war engine because it is a ground unit, but if you disembark and embark in the same turn then you can't disengage until the following turn. Unfortunately the FAQ is talking about consolidation moves in assault so it is not crystal clear, but it seems to follow.