I had been thinking that the 11 hour flight between Paris and Cape Town would be my longest in air. However, Jason kept mentioning my trip to Asia. However, I flew from Vancouver to Beijing so it wasn't as far as doing a direct from Toronto - I didn't think it had been that long.
Looking back in Always Standing it turns out he was right, that flight to China was almost 14 hours long. (According to what I wrote on July 25, 2010.)