Eles são quase inteiramente CGI ....
... e composições em tela azul de ação ao vivo.
Há um resumo e um artigo abrangente em FXGuide juntamente com um vídeo da casa FX (Method FX) sobre como foi feito.
Method Studios took on initial previs to further refine the actions for the three crashes, in addition to combining some gimbal-filmed shots and repelling soldiers shot on bluescreen.
The helicopters were modeled in Maya and textured in MARI. "Rivets are right on the cusp of that effort," says Rankin. "If you put them into the model, they're going to give you really nice lighting characteristics. As the light angle changes on the rivets, they pick up nice highlights. But it also makes for incredibly inefficient rendering. In this case we chose to leave the rivets in the textures, and only had to do some extra work for a few shots."