I think it's a new movie, this one guy is alone on earth, surviving, when all of a sudden he looks up and sees a space ship with humans in it, he is surprised to see there are actually still humans, this was how the movie was advertised as a trailer for 2013( the guy then gets on the space ship and I think they explain to him how they survived)

I'm pretty sure you're talking about Oblivion with Tom Cruise and Morgan Freeman. http://www.imdb.com/title/tt1483013/?ref_=sr_1