SAN FRANCISCO -- US aircraft manufacturer Boeing said Saturday that it has completed the first test flight of its new version of 777X twin-engine wide-body passenger jet.

The aircraft, which took off from Everett, Washington state, flew almost four hours before it landed at Seattle's Boeing Field, said the company. Two prior test attempts were called off due to high winds this week.

"Today's safe first flight of the 777X is a tribute to the years of hard work and dedication from our teammates, our suppliers and our community partners in Washington state and across the globe," said Stan Deal, executive vice president of Boeing and president and CEO of Boeing Commercial Airplanes.

The 777X plane, with two foldable wings spanning more than 235 feet (about 71.63 meters), is the world's largest twin-engine commercial aircraft. It is 10 percent more cost-effective and 10 percent more fuel efficient.

Boeing said it expects to deliver the first 777X aircraft in 2021 after receiving orders from the world's leading air carriers, including Japan's All Nippon Airways, British Airways, Cathay Pacific Airways headquartered in China's Hong Kong, and Singapore Airlines.

The company said earlier this month that it delivered a total of 380 commercial airplanes in 2019, its lowest number since 2008. The figure fell by 53 percent compared with the previous year.

The company's poor sales record was attributed mainly to the 737 MAX crisis, after two MAX jets were involved in two fatal crashes in October 2018 and March 2019. The two crashes killed a total of 346 people in Indonesia and Ethiopia.

All MAX aircraft have been grounded globally since March 2019. Their return to service has been delayed several times after Boeing failed to obtain certified approval from U.S. federal regulators.