Fierce rivals Airbus and Boeing lock horns in a battle for lucrative airliner orders, mainly from fast-growing Gulf carriers, as the Dubai Airshow opens on Sunday.
Boeing is expected to have the upper hand with the official launch of its new 777-X long-haul airliner, and Dubai's Emirates expected to place a large order.
The wide-bodied airliner, featuring lower fuel consumption engines and composite wings, should in 2020 replace the current 777, the US maker's workhorse launched in 1990 and a Boeing bestseller with 1,473 sold by November 12.
Boeing is fielding the 777-X to counter Airbus's long-haul A350-1000.
This is anticipated to enter service in 2017 with a capacity of 350 passengers, and threatens Boeing's predominance in the long-haul market.
Even before its official launch, "many companies have shown interest" in the 777-X, said analyst Yan Derocles, from Oddo Securities.
Emirates is expected to lead the way, after its president Tim Clark told the Financial Times last month that the Dubai carrier intended to make a "substantial" order for the 777-X.
The paper estimated that Emirates, already the largest single operator of the classic 777, will want between 100 and 175 of the new version capable of holding 400 passengers.
But Airbus is set to put up a strong fight.
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"I do not see Airbus folding its arms and counting Boeing's orders," said one aviation expert who asked not to be identified.
"Sunday will be a good day for Airbus. It should make announcements for (orders for) its A350 and the Neo" lower fuel consumption medium-haul A320, an industry source said.
The Dubai Airshow is the last major aviation event in the year, so manufacturers "are keen to end it well", said analyst Christopher Menard of Kepler Cheuvreux.
Abu Dhabi's Etihad Airways and Qatar Airways, the Gulf's two other fast-growing large carriers, are also likely to place big orders.
Airbus is far ahead of Boeing with 1,215 orders by the end of October, compared with 957 orders for Boeing.
But Airbus is struggling to sell its A380 superjumbo that has yet to receive an order this year.
Sales of the world's largest commercial aircraft suffered in 2012 after hairline cracks were discovered on A380 wings. Just nine were sold last year, down from an initial order of 30.
The final airshow order book could beat records, said Jean-Louis Dropsy of Kurt Salmon consultancy -- even the previous record set in Dubai in 2007 when sales reached $155 billion (115 billion euros).
Dropsy said Boeing sales already expected this year would hit $80 to $100 billion, to which Airbus and private jet sales will then be added.
In June, the Paris air show at Le Bourget racked up $115 billion in announced sales at catalogue prices.
The 13th Dubai Airshow, which runs until Thursday, will be at the just opened Al-Maktoum International, the emirate's second airport and touted to become the world's biggest once complete.
With some 150 aircraft displayed on the tarmac and with 1,000 exhibitors, the show cements the Gulf region's hard won position as the global hub for 21st century travel, spearheaded by booming airlines whose reach encompasses the world.