Allegheny County Police on Thursday investigated a security threat impacting a plane chartered by the Pittsburgh Symphony Orchestra.

A note “that was deemed to be potentially threatening” was found at Pittsburgh International Airport around 10:35 a.m. Thursday, Jim Madalinsky, a county police spokesman, said Friday.

The county’s bomb squad swept the plane and the passengers aboard, he said, before officials determined the note “was not threatening in nature.”

Airport operations were not affected, Madalinsky said.

Keene Carter, a spokesperson for the symphony, said the plane was bringing most of the orchestra’s members — along with support staff and several donors — back from a sold-out concert at New York City’s Carnegie Hall.

Officials did not explain in detail what was happening but told the symphony members “a security threat had been identified,” Carter said.

“We remained calm, deplaned, were cleared to go, and are grateful to the authorities and airport for the swift response and professionalism,” he said.

A spokesman for Pittsburgh International Airport did not immediately respond to a request for comment Friday morning.