Our current mayor, or his campaign workers, have decided that "a waterfront for people not planes" has the mindless appeal of a good political slogan. Except that if you stop to think about it, the slogan has some pretty offensive implications.
Personally, I'd like to make my neighbourhood a place for people, not musical instruments. I'd like to make my house a place for people, not art. And I'd sure like to see the city turned into a place for people, not law offices and courts. I could go on, but I hope I have made my point: people come with art, music, law, justice, and we also come with travel and technology. And it doesn't do to call planes things, from which we can easily separate people. If I take the art from the artist, the fiddle from the musician, the law books and courts from the lawyer, I have effectively undermined their freedom to express themselves; I have diminished their humanity. And if I take the plane from the aviator, I have done the same thing.
Now, I suppose you could make an argument that planes harm the downtown environment; but that slogan says nothing about the environment. And if you did try to make a case that Toronto City Centre Airport harms the environment, you'd have to address a huge body of evidence that moving traffic from Pearson to Toronto City Centre Airport actually reduces pollution in the Greater Toronto Area overall. And in any case, the mayor's campaign can hardly argue against aviation with any consistency, since he's started pushing a plan for an expo in 2015, which will depend on air travel to succeed, in the unlikely event that it does.