Emirates Airlines has ordered 50 long-range Boeing 777 passenger jets worth a combined $18 billion dollars, the Dubai-based carrier's chairman and chief executive said Sunday. "Emirates has placed an order for an additional 50 Boeing 777-300 ER" planes, in addition to 20 Boeing 777-300ER as an option, Sheikh Ahmed bin Saeed Al-Maktoum told reporters at the Dubai Airshow. "This order represents a milestone. It is the single largest dollar-value order in Boeing's history," said the head of the largest carrier in the Middle East. Sheikh Ahmed put the total value of the firm order and options at $26 billion, adding that the latest announcement brings Emirates' orders of the long-range aircraft to 90 from 40 units. Emirates, which is one of the worlds fastest growing carriers, last year placed an order for 30 Boeing 777 planes worth $9.1 billion at Britain's Farnborough show.