This can only be done in the late game with the UEF because it equires an Atlantis T4 Submersable Aircraft carrier and because you need the Stinger T2 gunship. This strategy allows you to launch land units from your Atlantis.
First you need to build an Atlantis Sub, then build the desired land force consisting of T1 or T2 units only. Next, build an equal number of gunships. Load the land force onto your gunships: you will now be able to garrison them in your Atlantis. Once you reach the desired position, send your Stinger force in to drop the land units off (destroying at least some AA beforehand is not a bad idea!). Now you have a sizeable army at the drop point and a ton of air support. If your target is near the coast, leaving the Atlantis nearby to provide support fire and replacement air support isn't a bad idea.