Originally Posted by
The Ancient Geek
The SP was a strange beastie, not very many were sold. I believe there are still one or two still in service.
I had the pleasure of a free upgrade to upstairs on one of its shortest routes, back in the 70s it did Joburg to Durban on wednesdays only while the A300 was in the hangar for a weekly service.
The 747SP was always intended to be a 'niche' aircraft - basically trading payload for vastly increased range (not unlike the 777-200LR today). Boeing sold 45 747SPs which was probably about what was expected. Recall that the economics of aircraft development were much different in the 1970s - certification costs were much lower and no one expected big widebody aircraft to sell in large numbers so development costs were amortized over a smaller number.
It looks like there are ~15 747SP still 'active' - although I doubt any of those are in regular scheduled service. Several are being used for testing or research (FAA has one, NASA has SOFIA, and Pratt & Whitney has two for engine development flying test beds) and the rest appear to be VIP/biz jets (a casino in Las Vegas has a couple that they used to fly around their high rollers).