Just to clarify this:
Quote:
Q:Can units transported by Planetfall (for example Assault troops in a Thunderhawk) disembark as soon as the transporting unit lands?
A:The intent of the Planetfall rule is that units landing via Planetfall get to land for free early in the turn, and then function as if they had been on the table since the start of the turn. This means that they can take their action later in the turn, as they won’t have used it up yet – they are literally counted as having done nothing during the current turn.
Units on board WE or other transport can choose to disembark immediately when they land or they can remain on board. If they choose to remain loaded they act as a normal mounted formation. Regardless of the choice to disembark or remain embarked, the formation may take an action on the turn it lands, as the process of landing and disembarking is free – in other words, just a way to get the units onto the table as part of the spacecraft’s activation. Note if a formation chooses to remain embarked on a War Engine transport, 3.1.3 will apply as normal.
From the FAQ.
The full Planetfall FAQ is on page 51 of the NetEA Tournament Pack 2012 and answers quite a few questions about this.