The North American headquarters of All Nippon Airways has been raided by the FBI, forcing the carrier to suspend ticket reservations for several hours.
ANA is Japan's second biggest carrier
No reason has been given for the search of the Los Angeles premises - but the airline said that terrorism was not behind the incident.
Last year the US government that it was probing possible price fixing in the air cargo industry.
ANA said it did not know if the raid was connected to that investigation.
"We are trying to establish the purpose of the raid but it is not connected with flight operations or terrorism," ANA said.
"Our flight ticket reservations were suspended temporarily but have now returned to normal."
ANA is Japan's second-largest airline by income, flying to 50 destinations in Japan and 24 cities across Asia, Europe and the US.