The US aviation regulator has said 171 Boeing 737 Max 9 planes will remain grounded until it is satisfied the planes are safe.

The Federal Aviation Administration has been inspecting the jets after part of an Alaska Airlines plane’s fuselage fell off last Friday.

Thousands of passengers saw their flights cancelled after major US airlines grounded dozens of the jets.

During Friday’s incident, Alaska Airlines flight 1282 from Portland, Oregon, to Ontario, California, reached 16,000ft (4,876m) when it began an emergency descent.

Passengers on board said a large section of the plane’s outer shell fell to the ground shortly after take-off.

Boeing’s 737 Max has been described as “the most scrutinised transport aircraft in history” after a series of safety issues.

The Max was grounded in March 2019 for a year and a half after two of the type crashed in similar circumstances to each other, killing those on board.