Boeing Co said on Monday it won an order for 14 freight aircraft for a value of $4.7 billion, firing the opening salvo against rival Airbus SE in a contest for business on day one of the Farnborough Airshow.

Logistics group DHL placed the order for the 777 freighters and acquired purchase rights for seven more freighters, the US planemaker said.

Boeing and Airbus are expected to make several announcements on the first day of the July 16-22 event, as they seek to bolster their already bulging order books.

The latest order follows Boeing's deal with FedEx Corp unit FedEx Express in June for 24 medium and large freighters.

While global trade tensions are escalating, the industry is counting on e-commerce continuing to soar, with more people buying products online for quick delivery.

Air freight demand is expected to increase 4% this year, according to the International Air Transport Association (IATA).

Last year was the best for cargo since 2010, with traffic growth more than doubling to 9%, three times the growth in capacity.

Boeing's latest order will double the size of DHL's global 777 fleet, the companies said. The delivery of the first four planes is expected to be completed in 2019, DHL said in a separate statement.

The Farnborough Airshow is the industry's biggest event this year. It alternates with the Paris Airshow and, collectively, they account for over a quarter of industry order intake each year.