I used to fly PA60/61 a lot, the IAD-FRA RT, in Clipper Class. In the mid-to-late 1980s this run was luxurious, sad and fascinating all at once. Luxurious because C class was 2-2-2 in a 747. Sad because the cabin got ever more empty over time, especially after Lockerbie. Fascinating because a lot of spooky Washington types used to ride that flight -- sometimes you'd swear half the State Department or NSA was on there with you.
What was your last Pan Am flight? Mine was not the FRA run from Dulles but the LHR run, PA106/107, in early 1990, just before they sold the Heathrow rights to UA. Those flights weren't luxurious or fascinating, just sad. My fiance and I took advantage of a panic PA sale and paid $298 each to go over for the weekend, and even at those prices there weren't more than 100 pax on board these ancient, scorched, dingy 747-100s -- either way. The whole back Y cabin was curtained off and dark. It was like a ghost plane. The FAs went about their business looking tight-lipped and stoic, knowing the entire proud enterprise was doomed. We all stretched out and slept in the middle seats.
Iraq invaded Kuwait about four months later and cooked Pan Am's goose for good.