I just made an on-line reservation SEA/YYZ.

I was unable to get on-line seats on the return portion and called UAL to get assigned seats and upgrade. I was informed that the return portion was via Air Canada, that the best seats available were 24A & B and that there were no upgrade possibilities, by any method.

It is a direct flight, YYZ/SEA maybe 5 hours, so I was very disappointed. They did say, however, that I'll get my status miles and double miles.

Does anybody know about this stuff? Aren't they both Star Alliance? How does that work? Do I get PremEx Privileges? Early boarding, better seats, anything? Can I use my RCC card for the Air Canada lounge?

I am soooooo out of my element. I usually only drive to Canada.