The SEA-HKG run is one United had authority on prior to its purchase of Pan Am's Pacific division. Prior to that purchase and the subsequent acquisition of 747SPs, United had leased a couple of DC-10-30s from CP Air for that route amongst others. A United gate agent told me that the DC-10s often had considerable numbers of seats blocked in order to make the trip nonstop. However, he also mentioned that United did a brisk business in cargo on those flights to the extent that occasionally it may have been making as much or more money in the cargo holds than on the passenger deck.