Originally Posted by jlemon

21. (1969) You need to fly from Mexico City to San Juan, Puerto Rico. Unfortunately, all flights to Miami are sold out – even in First Class. Thankfully, you’ve discovered another option involving two nonstop flights aboard two airlines, each operating a different type of aircraft. Por favor, identify the airlines, the connection point and the two aircraft.

Time for wild guess numero two-oh..... Iberia operating a Super DC-8 from Mexico City to Santo Domingo and then connecting to a Pan Am 727-100 on to San Juan.

Now we're talkin'! Your itinerary and airlines are correct, as is the Super DC-8 MEX-SDQ. However, Pan Am was not running a 727-100 on this flight. And if it wasn't a 727-100, well, everybody and their grandmother knows that in 1969 it was a 707. Even the OAG shows 707 as opposed to JET. So, I'll save you the obvious tap-in. Here's the itinerary -

Iberia IB 972 Mexico City (MEX) 1245p-530p Santo Domingo (SDQ) DC-8-61 Tu Th Sa
Pan American PA Santo Domingo (SDQ) 745p-930p San Juan (SJU) 707-320 X25