As of today, no, you don't require a passport to fly to the US from Canada.
If you have one, however, your life is going to be soooo much easier
You do need your DL, picture id, and your birth certificate whatever you have. Some USC&I agents will only need to see one, some will want to see whatever you have)...your problem isn't necessarily getting *into* the states- although that's what we generally focus on

- it's getting *back* into Canada.
A passport is your very best proof that you are a Canadian citizen.
As of January 8, 2007, if you're flying and/or cruising, you will need a passport.
Driving into the States, then flying..picture id...and the rest, yes. (As of January 1 , 2008, you're going to need a passport, driving, flying, train, bus,..

)
Just be prepared for some additional screening, perhaps, and additional questioning.
http://www.ppt.gc.ca/help/faq.aspx?lang=e
HTH!!
