Landing

The description says it all: first the landing capsule itself does damage to the units that it lands on, and then a stormtrooper squad emerges and fights normally. The squad has all the properties of your normal stormtroopers (for example, it has the same upgrade level). Although you can't build a landing yourself, they are quite plentiful as rewards and in chests, so you should have no problem keeping a steady supply of these (assuming you don't go too crazy).

To avoid cheesy tactics like dropping a landing on your opponent's spawn point, you can generally only drop landings on (approximately) the half of the battlefield closer to your spawn point. On some maps this does still leave plenty of places where you can catch your opponent by surprise with a sneaky drop.