The world’s largest twin-engined plane, Boeing 777X has successfully completed the first test flight .
The 777X is a larger and more efficient version of Boeing’s successful 777 mini-jumbo.
Standout features include folding wingtips and the world’s largest commercial engines.
The 252-foot-long passenger plane had been due to launch this year but has been delayed by some technical difficulties.
Boeing says it has sold 309 of the plane – worth more than $442 million each at list prices.
