Flying to US: don't care, whatever is cheapest and has the least travelling time.
Flying in Canada: well, it's kinda hard not to fly Air Canada---unless you only want to go places that would cost less if you took a bus.

I haven't flown on many international airlines... tried Air Canada, Cathay Pacific, JAL, JAA,......and that's about it...haha. My favorite would be JAL (Japan Airlines)..I've flown with them several times. The flight attendants were so sweet... The first time I flew with JAL was when I was 12 and they gave me lots of attentions because at that time I flew with friends only (for a festival), not with my parents. They always tried to keep me entertained during the flight. Gave me some teenage magz, some playing cards, small sized monopoli!!!, some postcards...hahaha..... I've seen them giving extra attentions to other kids too. And one thing more, whenever someone called them, they would come immediately and they will come back with what the passangers wanted pretty quick too.