RDA personnel, AMP suits, stuff that goes BOOM, you name it.
The Dragon Gunships are, as you probably know, enormous. Though they are not transport planes, like the Valkyrie, but mostly used for warfare as can be seen in the movie during the attack on Hometree. What is inside it, is probably anything and everything you could ever want to be carrying with you aloft on above a warzone. So, indeed, lots of soldiers and AMP-suits that can be dropped in warzones as well as bombs, supplies and so on.