Barnzoboy - A friend did some snooping and we have possibly narrowed it down to Chicago Midway Airport!
The problem is that they have 13 L and 13 R, not just a plain 13. I would like to get a hold of a layout or map of Midway for the same timeframe of the late 1960s just to see.
I still find it funny that undercarriage is used by multiple shows.