My nominations:
- PIT-TOL
- PIT-ART
- SYR-ART
- PIT-PWM (I would've been in diapers, so not sure I actually took it)
- PIT-LHR with a stop in Montreal to pick up passengers. It was on BA in spring 1998, not sure if it was Mirabel or Trudeau
Of course, with the demise of US' PIT hub and SYR hublet, none of these flights exist today.