AC still flies little props CLE-YYZ and vice versa, right?
I remember flying US mainline CLE-YYZ in 1990, and I think CO was flying mainline jets then also. AC had already gone prop by then, but that's still a lot of seats for what would otherwise be a four-hour drive...
AC flies Dash8 Q-100s 2x daily CLE-YYZ.
CO flies a mix of Q-200s and ERJs.