I think that it will be wise to use your passeport for any trip even within Canada
As an answer to the previous reply, Last year on our trip back home we have seen at the Philadelphia airport, a woman with only an I.D. card answering at the gate to all the questions of the clerk about her, finishing by being able to enter the plane after severall minutes of "interview".
We arrived with our passeports and allowed to board without delay in the plane.
Never forget that the passeport is the ultimate identification piece, accepted all around the wolrd.
alexx ("Don't leave home without it")