Boeing has been boosted for its grounded 737 Max jet after British Airways owner IAG signed an intention to order 200 of the planes.
The airline said it was certain that the Boeing aircraft would come back for service in the coming months.
Boeing is currently attempting to develop a software solution for 737 Max aircraft after two fatalities.
All 737 Max aircraft were founded in March after an aircraft from Ethiopian aircraft crashed and killed 1
Five months earlier, 189 people were killed when a Boeing 737 Max crashed by Lion Air crashed.
By Theo Leggett, BBC Business Correspondent
This is not a firm order and IAG could change if it wanted – but it will still come as a huge boost for Boeing on a show where it has struggled to remove the clouds hanging over its business.
737 Max can still be grounded – but it remains a flagship product for the American giant. It is worth remembering that it is the fastest selling product in Boeing's history. It still has more than four thousand of them on order, much more than the rest of its range put together.
What IAG seems to have offered is a trust guarantee that the company will be able to make the plane undoubtedly safe and able to demonstrate to regulatory authorities that it has done so so that it can return to the market for too long .
The economic reality is that airlines need 737 Max – because of its high efficiency and low operating costs. Airbus simply cannot supply the entire market with its competitor A320neo.
The agreement, if it goes further, will be valued at $ 24 billion. Kr. (DKK 19 billion) For list prices. But the "substantial discount" negotiated by IAG's savvy CEO Willie Walsh is likely to be very significant.
Meanwhile, the message may help alleviate the mood of the Boeing chalet, where it would be understandable if any of a siege had developed over the last few days.
The aircraft will be used by IAG airlines, including British Airways, Vueling and Level, the airline said in a statement.
IAG Managing Director Willie Walsh said: "We have great confidence in Boeing and expect the aircraft to have a successful return in the coming months, after having been approved by the regulators."
IAG's "first priority is passengers' and the safety of the crew, "says a spokeswoman.
Boeing shares rose more than 2.8% after the announcement.
The company said it was "truly honored and humiliated by the management of the International Airlines Group to provide trust and confidence in 737 Max".