Singapore Airlines has been named the world's best airline for the fourth time in the annual World Airline Awards. The carrier also took out the awards for best first class, the best airline in Asia and best first class seat.

The Skytrax World Airline Awards were announced in London on Tuesday, coinciding with the Farnborough Air Show. The awards are based on surveys of more than 20 million travellers, who rated more than 335 airlines between August 2017 and May 2018.

Singapore Airlines knocked off last year's winner, Qatar Airways, for the top spot. Asian airlines dominated the list, with seven of the top 10 coming from the region. Lufthansa was the only European airline to make a list.

"A key 'wow' factor for customers is consistency, and this proved to a real asset for Singapore Airlines who scored highly across both product and service," said Skytrax CEO Edward Plaisted.

Singapore Airlines CEO Goh Choon Phong accepted the award in London and dedicated it to the airline's 26,000 staff.

2018 is shaping up to be a big year for Singapore Airlines. In October, it will relaunch the world's longest flight route by resuming non-stop services between Singapore and New York. The airline will fly the first Airbus A350-ULR (for Ultra Long Range) on the 16,700 km route, taking almost 19 hours. There will be no economy class on the plane, which will feature only business and premium economy seating.

In the past 12 months, the airline also rolled out new seats for its A380 superjumbos, including its first double-beds in business class.