The American airline Delta Air Lines announced on Monday a firm order for 100 models of the 737 MAX 10, the medium-haul aircraft from American aircraft manufacturer Boeing, at the Farnborough Air Show in the United Kingdom.

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The order, which at the list price of the MAX 10 totals around $13.5 billion, is another sign of renewed airline confidence in the aircraft which had been grounded for months following two fatal crashes.

The agreement also includes an option to purchase 30 additional aircraft. Deliveries are to take place from 2025.

“The Boeing 737-10s will be an important addition to Delta's fleet as we shape a more sustainable future for air traffic with superior customer experience, more efficient fuels and the best possible performance,” said in Delta boss Ed Bastian said.

In addition to Delta, Boeing has secured an order for 20 MAX 8 aircraft from Japan's ANA airline, with an option to purchase 10 more aircraft, which represents about $2.4 billion at list price.

Ana has also placed an order for 2 long-haul 777-8s that the company plans to use for air cargo.

The agreement with Delta also includes the reconfiguration of the interior of 29 Delta 737-900 models, which must be ready to fly in the summer of 2025.

Delta is the last of the major American companies to order MAXs.

The MAX 10, the newest and largest version of Boeing's single-aisle aircraft, has not yet been certified by the United States civil aviation regulator (FAA), unlike the MAX 8 and MAX 9.

Its fate rests in particular in the hands of the US Congress, which must decide by the end of December whether or not to grant an exemption to a law imposing new standards for the crew alert system.

A lack of certification would imply additional training for pilots, making the model more expensive for companies, which could turn away from it.

The US regulator has tightened the screw for Boeing's certification after two close fatal crashes of MAX 8. The aircraft had been grounded for 20 months, from March 2019 to December 2020.

The Farnborough airshow, which opened on Monday, runs until Friday, with decarbonization and the sustainable future of aviation as the main themes.