Emirates Airline placed an order for 50 Boeing 777 aircraft on Sunday at the start of the Dubai Air Show, as the carrier appeared set to maintain its steep expansion path.

The order, which includes an option for further 20 aircraft, is worth $26 billion (16 billion pounds) including the options, the airline's chairman said.

(The) 777 has served Emirates very well in terms of seat costs ... especially when we see the fuel price is quite high, Emirates Chairman Sheikh Ahmed bin Saeed al Maktoum said at a press conference.

Reuters reported on Friday that the Dubai government-owned airline was in negotiations to buy between 30 and 50 Boeing 777 mini-jumbos, expanding its role as the world's largest operator of Boeing's most profitable plane.