The Federal Aviation Administration lifted a grounding order late Wednesday.

They had been out of service following the midair blowout of a big panel on one operated by Alaska Airlines.

Now the FAA says the aircraft can fly again once inspections are completed.

That's a big relief to Alaskan and United - the type's two main operators.

They've been forced to cancel thousands of flights.

But the FAA also barred Boeing from increasing output of the model.

Regulators said they wouldn't approve any rise in production until they were satisfied that quality control issues had been addressed.

The ruling is a big blow for Boeing, which had wanted to boost output to close the gap with European rival Airbus.

Speaking after a meeting with lawmakers, Chief Executive Dave Calhoun sought to reassure travellers:

"We believe in our airplanes. We field safe airplanes. Our people do. We have confidence in the safety of airplanes. And that's what all of this is about. We fully understand the gravity."

Production of MAX jets was supposed to hit 38 per month by the end of last year, rising to almost 58 per month in late 2025.

Now plans to set up an extra production line could be in doubt, with the FAA not saying when its curbs would end.

Analysts say the impact of the restrictions could ripple right across the industry, as the MAX jets are a big source of business for suppliers.

In better news for Boeing, the company has delivered one of its MAX jets to China for the first time since early 2019 - a breakthrough for the firm in one of the world's most important aviation markets.

Beijing had halted deliveries of the planes following two fatal crashes that were traced to a design flaw.