Leaving on Saturday for Alaska and Vancouver and am flying back on August 17 out of YVR on Delta. 6:00 AM flight (couldn't do anything about it...the tickets were free, and I mean totally free as Ms1995 won them in a raffle at an office Christmas party). Never been to Vancouver before and I'm wondering how the process works there for international flights. I am told that you have to stand in line to pay an airport improvement fee and that you clear US Customs and Immigration there. The question is--how does the security work? Do you stand in yet another line for screening, and are the Canadians as irritating as the TSA? I was planning on trying to get there between 4 AM and 4:30 for the 6:00 flight. Is that reasonable?

Thanks in advance.