Speaking of Cancun...I just booked a flight in late Feb from SFO to CUN. I haven't flown out of the country in a long time and I was wondering about how early I should show up at the airport for the trip back and if there are any other travel issues I may have to deal besides having a valid passport, no illegal items etc. Any advice especially about the Cancun area would be appreciated. Hopefully I can snag an upgrade both ways...