"The humans knew that one day the aliens would come back," states Emmerich, whose other world-ending efforts include The Day After Tomorrow and 2012. "And they know that the only way you can really travel in space is through wormholes. So for the aliens, it could take two or three weeks, but for us that’s 20 or 25 years... It’s a changed world. It’s like parallel history. [Humans] have harnessed all this alien technology. We don’t know how to duplicate it because it’s organically-grown technology, but we know how to take an antigravity device and put it in a human airplane."
Emmerich then went on to state that the movies could go ahead without the original cast members, specifically Will Smith, although the stepson of his character Captain Steven Hiller will play a big role in proceedings: "It’s still some of the same characters, but also new younger characters; it’s a little bit like the sons take over. The first [sequel] ends on a little success, but only enough to give the humans hope. And then in the second one they free themselves again [from the aliens]."