The order, revealed on Sunday, the opening day of the Dubai Air Show, came after a $4 billion deal for Boeing to supply 70 of its 737 aircraft to eight Chinese airlines, increasing its dominance over Airbus in China.
Boeing and Airbus - marketing its new super jumbo, the A380 - are fighting to sell jets to carriers in the Middle East, one of the world's fastest-growing markets and which has been largely unaffected by surging fuel prices and terror threats.
"We are investing in more new aircraft to meet the escalating demand for Emirates services from our customers across the globe. This new order will support the airline growth plans and enhance our fleet range and versatility," Emirates chairman Shaikh Ahmad bin Saeed al-Maktoum said.
"This is a firm order worth $9.7 billion ... . The contract will have a purchase right for 20 more," he said.
Emirates, one of the fastest-growing carriers in the skies, also signed an agreement worth up to $3 billion with General Electric of the US for GE-90 engines to power the new, wide-bodied Boeings.
The Boeing order dwarfs the nearly $7.5 billion in deals signed at the last show two years ago, including $3 billion in orders for Airbus jets by Qatar.
Airbus meanwhile secured comparatively modest orders for 18 aircraft from two Kuwaiti companies in deals worth $2.4 billion.
Emirates boss al-Maktoum: Deal
has buying rights for 20 planes
Kuwait-based aircraft leasing company ALAFCO ordered 12 Airbus A350-800 aircraft valued at $2 billion, while its no-frills compatriot, Jazeera Airways, ordered six single-aisle A320 aircraft, valued at $387 million.
Indian private Kingfisher Airlines ordered 20 ATR 72-500 aircraft, manufactured by the Toulouse-based Avions de Transport Regional. The deal is valued at $350 million with an option for 15 additional aircraft, the company said.
Boeing and Airbus have identified the Middle East as a high-growth area where demand is expected to outstrip expansion for the world market and about 1000 new planes will be needed in the next 20 years.
Boeing has estimated that air traffic in the region over the next two decades will increase by 5.5% per year, while Airbus is expecting an annual expansion of 7.1%.
Emirates has ordered 45 Airbus A380s as it embarks on an ambitious quest to turn Dubai into a major hub linking Europe to Asia, Australia and Africa.
The Airbus A380, the world's biggest passenger jet, made its maiden flight to the Middle East on Saturday, arriving in Dubai on the eve of the aviation show.
The head of Qatar Airways said he was unfazed by the big plans of Emirates and the entry of Etihad Airways, which was launched in 2003 by the government of Abu Dhabi, the richest of the seven emirates that make up the federation of the United Arab Emirates.
"There is enough business and enough expansion opportunities for all of us," CEO Akbar al-Baker told AFP. "We want to stay a very up-market, very passenger focused and very service-oriented airline."
"There is enough business and enough expansion opportunities for all of us"
Qatar Airways CEO
He said that although Qatar Airways will not be making any new order announcements in Dubai, it is still in the market for new planes. It had placed an order for 60 Airbus A350s and 20 Boeing 777s at the last major air show at Le Bourget in France in June.
So far, Airbus has received more than 150 orders for the A380, with options for another 100. It counts among its other customers Qatar Airways, Abu Dhabi's Etihad Airways, China Southern Airlines and Thai Airways.