International Airlines Group (IAG) has signed a letter of intent with Boeing for 200 737 Max aircraft to join its fleet.

The mix of 737-8 and 737-10 aircraft is expected to be delivered between 2023 and 2027 and are likely to be used by IAG airlines including Vueling, LEVEL and British Airways.

The new generation Boeing 737 Max was grounded in March following the crash of an Ethiopian Airlines flight soon after take-off from Addis Ababa. It was the second disaster involving the aircraft – a Lion Air Boeing 737 Max crashed after take-off from Jakarta last October.

Boeing announced the completion of a software update of the aircraft’s Maneuvering Characteristics Augmentation System (MCAS), which it believes will address the problem on the 737 MAX, in May.

But the aircraft remains grounded pending agreement among US and global safety regulators on its return and the training requirements for pilots.

IAG chief executive Willie Walsh said: “We’re very pleased to sign this letter of intent with Boeing and are certain that these aircraft will be a great addition to IAG’s shorthaul fleet.

“We have every confidence in Boeing and expect that the aircraft will make a successful return to service in the coming months having received approval from the regulators.”

Boeing’s commercial division president and CEO Kevin McAllister said: “We are truly honoured and humbled by the leadership at International Airlines Group for placing their trust and confidence in the 737 Max and, ultimately, in the people of Boeing and our deep commitment to quality and safety above all else.

“We are delighted that the IAG team recognised the superior qualities of the 737 Max and has indicated an intention to return to the Boeing 737 family.”

IAG also announced an order of eight Airbus A321XLR aircraft for Iberia, and six for Aer Lingus, plus 14 options.

The airlines will be among the launch customers for the extra long-range narrowbody aircraft with the first deliveries scheduled for 2023.

The aircraft will enable Aer Lingus to start new routes beyond the US east coast and Canada. The Irisg carrier is already taking eight A321neo LR on lease with the first delivery due this summer.

The new aircraft type for Iberia will enable it to operate additional transatlantic destinations and increase frequencies in key markets.

Walsh said: “This will strengthen both Dublin and Madrid hubs providing new transatlantic routes and additional flexibility for connecting passengers. These aircraft will also bring further cost efficiencies and environmental benefits.”