The US airline regulator has ordered the grounding of some Boeing 737 Max 9 jets after part of one plane fell off during an Alaska Airlines flight.
The Federal Aviation Administration (FAA) said the inspections would affect 171 planes.
On Friday the Alaska Airlines flight had to make an emergency landing after take-off from the US state of Oregon.
United Airlines says it has carried out the inspections required by the FAA on some of its 79 Boeing 737 Max 9 planes.
Removing some of the aircraft from service was expected to cause about 60 cancellations on Saturday, the airline said in a statement.
Earlier, the FAA said it would “order the temporary grounding of certain Boeing 737 Max 9 aircraft operated by US airlines or in US territory”.
Required inspections would take around four to eight hours per aircraft, it said.
Turkish Airlines has also recalled its five planes of that model for checks.
In Friday’s incident, the Alaska Airlines flight from Portland, Oregon to Ontario, California, had reached 16,000ft (4,876m) when it began its emergency descent, according to flight tracking data.
The airline, carrying 177 passengers and crew, landed safely back in Portland.
The chair of the National Transportation Safety Board (NTSB), which is investigating the incident, confirmed on Saturday that nobody had been sitting next to the affected section.