25. When it comes to the winter schedule, most airlines operate wide body jets between the US mainland and San Juan, Puerto Rico. At worst you might have to settle for an off peak 707 or 727. But lookee here – one airline operates a twin engine jet on a single daily nonstop flight from the mainland - late at night no less! Identify the route, the airline and the aircraft operated.
HINT: No First Class was offered on this flight

In my answer to Q9 I mentioned Air France operating to the Caribbean from Miami, I wonder then if I inadvertently answered this question...

So my guess is AF on a B737 Miami->Port-au-Prince->San Juan