Longest flight was probably some flight from NA to Europe. My parents took me to Greece and other places when I was 2 so I don't remember it but I assume my longest flight was then.
Longest that I remember, however, is probably the flight from Vancouver to Toronto. I dunno what model plane I was on but it was one of the ones with two aisle seats and each seat had a TV in front of it and I remember thinking it was the coolest ever. XD; My shortest flight was probably the 45 minutes or so between Winnipeg and Saskatoon or the flight from Halifax to Newfoundland, though I have no idea exactly how long that one was.