Plane was a very old DC-9 that clearly showed its age. On the other hand, the flight was excellent and we even got a sandwich on the trip from Cancun to Mexico City. On landing I was to make a connection with American Airlines. The problem was that there was no one to help once we landed in Mexico City and it turned out that American Airlines was some distance away. I was lost for awhile, not realizing where in the airport I was or where American Airlines was, but I eventually found my way and made my connection. Other than the lack of assistance on landing, it was a nice flight although I think DC-9s are pretty outdated planes at this point.