Travelling on a Aeroplan ticket from Buenos Aries to Calgary we too missed our flight in Cancun on Jan 1/19 due to the minimum connection time (90 minutes) not being enough time. In Buenos Aries we were told by Copa Airlines that our luggage would go straight through to Calgary but it was offloaded in Cancun instead. Copa arrived on time but it took over an hour to go through immigration and wait for our luggage leaving us less than half an hour to go through customs and get to another terminal where Air Canada was. We were treated very badly at the Air Canada desk with them telling us it was Aeroplans fault and we would have to purchase another ticket on their plane to get back to Calgary which left in two days. Westjet had a flight out later that night so we had to purchase a ticket from them at a extra cost of $1300 in order to get home. Consider yourself lucky that Air Canada looked after you because we did not have that experience. It was New Years day with very little open, foreign language problems, credit card machines not working and almost no internet. We met another passenger from Argentina who also missed the AC flight for the same reason and Copa almost immediately refunded his WestJet ticket but Air Canada refuses to refund ours. I agree with you that you need at least 3 hours to transit through Cancun airport and I would not go back to that airport with less time than that.