A Boeing 737-800 arrived at its destination in southern Oregon with a missing panel on Friday after flying from San Francisco, according to officials – the latest in a series of recent incidents involving aircraft manufactured by the company.

United Flight 433 left San Francisco at 10.20am and landed at Rogue Valley International-Medford Airport in Medford shortly before noon, according to FlightAware.

The airport’s director Amber Judd said the plane landed safely without incident and the external panel was discovered missing during a post-flight inspection.

The airport paused operations to check the runway and airfield for debris, she said, and none was found.

Ms Judd said she believed the United ground crew or pilots doing a routine inspection before the next flight were the ones who noticed the missing panel.

A United Airlines spokesperson said via email that the flight was carrying 139 passengers and six crew members and no emergency was declared because there was no indication of the damage during the flight.

“After the aircraft was parked at the gate, it was discovered to be missing an external panel,” the United Airlines spokesperson said.

“We’ll conduct a thorough examination of the plane and perform all the needed repairs before it returns to service. We’ll also conduct an investigation to better understand how this damage occurred.”

The missing panel was on the underside of the aircraft where the wing meets the body and just next to the landing gear, United said.

According to the Federal Aviation Administration, the plane made its first flight in April 1998 and was delivered to Continental Airlines in December of that year.

United Airlines has operated it since November 2011. It is a 737-824, part of the 737-800 series that was a precursor to the Max.

Boeing said it would defer comment to United about the carrier’s fleet and operations.

In January, a panel that plugged a space left for an extra emergency door blew off a Boeing Max 9 jet in midair, just minutes after an Alaska Airlines flight took off from Portland, leaving a gaping hole and forcing pilots to make an emergency landing. There were no serious injuries.

The door plug was eventually found in the backyard of a high school physics teacher in south west Portland, along with other debris from the flight scattered nearby.

The Department of Justice has launched a criminal investigation.

On March 6, fumes detected in the cabin of a Boeing 737-800 Alaska Airlines flight destined for Phoenix caused pilots to head back to the Portland airport.

The Port of Portland said passengers and crew noticed the fumes and the flight landed safely.

Seven people including passengers and crew requested medical evaluations, but no one was hospitalised, officials said.

On Friday, Boeing recommended airlines inspect the cockpit seats the next time they perform maintenance on their 787s Dreamliner jets after a published report said an accidental cockpit seat movement likely caused the sudden plunge of a LATAM Airlines plane flying to New Zealand.

The company described its advisory as a “precautionary measure”.

It noted that the investigation into what happened during Monday’s LATAM Airlines flight between Australia and New Zealand was continuing and referred questions about potential findings to investigating authorities.

Passengers reported that when the Dreamliner dropped without warning, people not wearing seatbelts were tossed from their seats and into the cabin ceiling and aisles. The plane later landed at Auckland Airport as scheduled.

About 50 people were injured, according to emergency crews in Auckland.