04:15 PM EST, 12/30/2024 (MT Newswires) -- The US Department of Transportation said Monday it has fined Lufthansa $220,000 and Swiss International Air Lines $200,000 for flying in Federal Aviation Administration-restricted airspace while carrying United Airlines' (UAL) code.

An investigation found that between March 2022 and April 2024, Lufthansa violated FAA restrictions by operating multiple flights in prohibited airspace, breaching its operating authority, the statement added.

Similarly, Swiss International Air Lines was found to have operated flights in restricted airspace between Feb. 2022 and March 2024, also violating its operating authority.

Both airlines have been ordered to stop such violations and comply with the agency's regulations going forward, it said.