First the good news: You'll earn more frequent flyer miles for enduring 18 hours on a plane. But a seat will cost you a bit more.
United Airlines last week launched its nonstop service from Los Angeles to Singapore, a some 8,700-mile journey and the longest nonstop flight from the U.S. The airline listed fares on its site for $177 for the Los Angeles-Singapore leg of a round-trip flight. The round-trip fare came to about $384, including taxes and fees.
Those fares on the nonstop are gone for the rest of 2017, according to United's site and its customer service desk. Airfares change based on carriers' pricing algorithms, which factor in demand and seat availability, so it's not impossible for the fares to resurface, but it could be unlikely as the end-of-year holidays approach.
Roundtrip fares for those nonstops aboard United's Boeing 787-9 Dreamliner were about as low as $574 with tax for departures in early December and returning the third week of the month, as of Tuesday. The fares were roughly $700 at other times in the month.
Because United, like other airlines, rewards flyers based on how much they pay for their ticket, travelers would earn more miles on the latest fares than on the rock-bottom fare United had posted earlier.
United had not yet responded to CNBC's request for comment on the $177 fare but one airline analyst said that the airline could have sold the low fares — which work out to just under $10 an hour on the ultralong-haul flight — to raise awareness about the new service.
Airlines have been battling low-cost carriers in the U.S. and on trans-Atlantic routes, showcasing new food and beverages on board to stand out against no-frills airlines, and the low fare could be a way to get more travelers on board as competition for travelers crossing the Pacific emerges.