After nearly two years and a pair of deadly crashes, the US Federal Aviation Administration has cleared Boeing's 737 Max for flight.
The US air safety agency announced the move early on Wednesday, saying it was done after a "comprehensive and methodical" 20-month review process.
Regulators around the world grounded the Max in March 2019 after the crash of an Ethiopian Airlines jet.
That happened less than five months after another Max flown by Indonesia's Lion Air plunged into the Java Sea.
A total of 346 passengers and crew members on both planes were killed.
The planes won't return to the skies for a while.
The FAA said it must approve pilot training changes for each US airline and airlines must perform required maintenance on the planes.
The FAA said the move was made in co-operation with air safety regulators worldwide.
"Those regulators have indicated that Boeing's design changes, together with the changes to crew procedures and training enhancements, will give them the confidence to validate the aircraft as safe to fly in their respective countries and regions," the FAA said in a statement.
The move came after numerous US congressional hearings on the crashes that led to criticism of the FAA for lax oversight and Boeing for rushing to implement a new software system that put profits over safety and ultimately led to the firing of its CEO.