Someone seems to bring this up to me at least once every few months, and this time it brought me back to read airplaneonatreadmill.com again. Of all the idiotic discussions on the internet about this topic, I am so happy that a smart person got ahold of this domain name and completely cleared the air. The money quote:
But what is the question really getting at, anyway? There are really two “spirits” of the question. In the first, we’re asking “can a plane take off with no runway, if I replace the runway with a treadmill?” The answer, as we know now, is no. The plane must move relative to the ground in order to take off. In another deep-meaning of the question, we’re asking “is it possible to prevent a plane from taking off, by moving the runway backwards under it?” The answer again is no, you can’t prevent it from taking off.
It’s things like this that restore my faith in humanity.