Ever since I read the theory I'm about to present I've kept thinking it is true. Basically, with this new sequel, Treyarch could have gone anywhere from 1930-2020, and I'll tell you how. In black ops, we were in the 1960's, but kept on having flashbacks, and most of the play-time in the campaign were in these 'flashbacks'. Now here comes what I believe to be the main plot of black ops 2. We are the same person, perhaps not strapped to a chair again, but nonetheless, the same person, but now, we're in 2020 and having flashbacks of what happened right after black ops finished. This is how treyarch could have taken this storyline anywhere. They could have made it so that you're in 2020, but having flashbacks of 1980, but for most of your gameplay you are in 2020, and only occasionally have flashbacks and play in the past. Or, they could make it so most of your play time is in the past rather than the future. This is where all the Quad-rotor mystery clears up. You are in 2020, so the quad rotor exists. I mean, it really isn't that advanced (looks like something I could get at brookstone ) , but since you're in 2020, you can still use the Quadrotor, but since you are having flashbacks to the 1980's, you are still picking up where black ops left off. This way, you could have the best of both worlds, and it seems like the best choice that treyarch could have done.