The world's longest flight is coming to an end this weekend. Singapore Airlines will no longer fly the direct business-class between Singapore and New York.

The 18.5 hour flight from Changi to Newark costs around $8,800 is being cancelled, which is upsetting to some business travelers who utilized the route. They will now face an extra six hours or more in travel time.

"It's disappointing that a direct flight to the U.S. is no longer available. I feel that it was decently full every time we were on it. The timing of the direct flight works best for business travelers," Singapore-based Sheena Mahtani told CNBC.

"The SQ flight via Frankfurt would probably be the only other Singapore-New York option that would work," she added, referring to the flight with duration of over 24 hours.

Singapore Airlines' non-stop flights to the U.S. has been very beneficial to the airline as it helped it win and maintain corporate accounts, the Centre for Asia Pacific Aviation (CAPA) says, according to CNBC.

"There was also the glamour and prestige associated with operating the world's longest non-stop routes. But ultimately the incredible cost of operating an ultra-long-range service could not be ignored," CAPA said in a recent report on long-range travel.

However despite its benefits, the high operating costs were much more than the revenue brought in from the flight, so it wasn't worth it to continue.

The airline reconfigured the flight in 2008 by changing it to 100 business class seats from 117 premium economy and 64 business class seats. In that year, premium made up9.5 percent of all of the passengers. It has since dropped to eight percent.

"At the current high price of fuel, making a profit off such long flights became nearly an impossible mission even when filling the plane with premium passengers," CAPA said.

Singapore Airlines also ended its nonstop service to Los Angeles in October, but it is still committed to the US market.