Regarding car rental upgrades, you just have to ask.
However, with the above tactics, I never flew economy from Vancouver to New York. Thats live flat seats business class with Cathay Pacific.
I flew there three times in the past six months. The problem from JFK is, that British does all their bookings and they don't have the power to upgrade (unless you call Cathay before with a valid complaint).
Recently when I was in the Presidents Club in Newark, the agent told me that all the Jewish people always ask for an upgrade. So good luck with Continental in Newark, they have to deal with all the Israelies on their night flight to Tel-Aviv.