We flew on the longest flight in the world in both business class and premium economy to see how they compare — here's what we discovered

• Singapore Airlines recently relaunched its nonstop service between New York and Singapore.
• The 10,000-mile flight can last as long as 19 hours; it's the longest in the world.
• Singapore Airlines is using a fleet of brand-new Airbus A350-900ULR airliners to make the flight.
• The new fleet has 161 seats in business and premium-economy classes. There is no economy section.
• Business Insider recently had the chance to experience the trip in both business class and premium economy to see how they compare.

In October, Singapore Airlines relaunched its nonstop service between New York and Singapore. The 10,000-mile journey can last as long as 19 hours, making it the longest scheduled passenger flight in the world.

Singapore Airlines operated the route from 2004 to 2013 using the Airbus A340-500. While it has exceptional range and capability, the A340-500 was a relic of the 1990s, and the thirst of its four engines proved too uneconomical to sustain. Even a shift to an all-business-class layout couldn't generate enough income to save the route.

To operate the ultra-long-distance flight, the airline ordered a fleet of seven Airbus A350-900ULR — Ultra Long Range — aircraft.

The first flight marked the operational debut of the ULR variant, which one Singapore Airlines executive said was the only aircraft capable of making the flight in an economically viable fashion.

The biggest difference between the standard A350-900 and the ULR is its range. Airbus managed to cram an additional 6,300 gallons of fuel into the plane's tanks, increasing its range to as much as 11,100 miles from 9,300 miles.

Each ULR aircraft has 161 seats in two classes, business and premium economy. It's one of the few scheduled commercial airline flights without an economy-class cabin.

Singapore Airlines is also using its fleet of ULRs to launch nonstop flights between Singapore and Los Angeles, as well as Singapore and San Francisco.

Business Insider recently had the chance to experience the New York-Singapore flight in business class and the return flight in premium economy. Here's how the two stack up.

SEE ALSO: Check out the secret compartment where flight attendants sleep on the longest flight in the world

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The new Airbus A350-900ULR awaits.

Here's a better view of the jet.

Let's get on the plane.