From the start, the 737 Max was meant to be a simple way for Boeing to respond to the popularity of the Airbus A320neo. While a final re-engining for the 50-year-old design posed some challenges, it was seen as quicker and simpler than delivering a clean-sheet model. Fitted with CFM International Leap-1B engines, the Max promised to deliver a fuel-burn saving of around 15% over its 737NG predecessor.

But instead of maintaining a steady source of revenue each year, the Max has cost Boeing immeasurably: its reputation has been shredded; a chief executive has departed under a cloud; orders have evaporated; and billions of dollars in revenue have been lost. The crisis also could not have come at a worse time, leaving the US giant weakened just as the coronavirus pandemic struck.

And amid the focus on Boeing’s lost billions, it is worth remembering the human cost as well: two separate crashes of 737 Max 8s cost 346 people their lives.

Two years on since the Ethiopian Airlines crash which sparked the global grounding of the type, a string of regulators have approved the Max return to service and airlines are gradutally resuming commercially resuming operations with the type. But much has changed for Boeing for airlines and for regulators overthe past two years.