The 777X, which is a larger and more efficient version of the successful Boeing 777 mini, took off outside Seattle at 10:09 am local time (1809 GMT) after high winds forced the company to delay two previous attempts this week.
Boeing officials said that the first flight of the long-distance plane, will take 3 to 5 hours and will be the start of months of tests before entering service in Emirates Airlines in 2021, that is, a year after the date originally planned due to obstacles during development.
The company posted on its Twitter page a video of the first test flight
This aircraft is the largest of two new Boeing models.
Among the most important advantages of the plane, its two wing-foldable wings to enter the garage of previous versions of Boeing, in addition to its giant engine developed by General Electric.
The flight is a major boost for Boeing, which faces a major crisis on its 737 MAX, which was shut down in March after two fatal accidents.
The 777X, with a capacity of 384 to 426 passengers, is designed to compete with the Airbus A350. Boeing has received orders for 340 of this type, the majority of which are from seven huge international airlines, including Emirates, Lufthansa, Cathay Pacific, Qatar Airways and Singapore Airlines.