5. (1987) You need to fly from Burbank, CA to Montreal, Quebec next month. Your travel agent has booked you a three flight itinerary involving three airlines, each operating a different model of aircraft, each built by the same manufacturer. One of the airlines is foreign and operates a widebody on the final leg. Each aircraft will also have a different engine configuration. None of the aircraft were built north of the 45° parallel. Identify the routing, the three airlines and the three aircraft types.
One of the weird but popular 5th freedoms in the day was JFK-YUL which was operated at least by AR with a 747-200 in that era, and IIRC in(to) the early '00s by BA with a 757-200(!). The one I think may be the right candidate is RG with a 10-30.
So my guess is
PS BUR-SFO with an MD-80
UA SFO-JFK with the D8S, and
RG JFK-YUL with the DC-10-30