The European Commission has presented a strongly worded letter to the United States warning it not to prevent Air Italy (Milan Malpensa) from flying to the US, Air Transport World has reported.

The warning comes as American Airlines, Delta Air Lines and United Airlines scale up a combined challenge to Air Italy’s rights to fly to the US, accusing it of acting as a proxy for Qatar Airways, which has a 49% stake in the carrier. The carriers have launched a media campaign in US newspapers and lobbied Congress, claiming Air Italy’s services are in effect Qatar Airways fifth freedom flights.

The letter, by Henrik Hololei, director-general for mobility and transport, and addressed to Manisha Singh, who was until the end of June the acting US undersecretary of state for economic growth, energy and the environment, states that the commission “will take all steps necessary to defend the rights of the European Union, its Member States and its air carriers” under the EU-US Open Skies agreement.

Air Italy currently operates four routes to the US from Milan Malpensa, year-round to New York JFK and Miami International and summer only seasonal services to Los Angeles International and San Francisco. However, Chief Operating Officer Rossen Dimitrov told ch-aviation on the sidelines of the IATA AGM in Seoul in early June that the airline was planning to add more routes despite the US carriers' ongoing protests.

“I have come to understand that, following persistent but unfounded demands from certain parts of the US airline industry, the US administration is potentially considering taking measures against the services of Air Italy to the United States. In this context, I would like to bring to your attention our serious concerns," Hololei said in the letter.

“Air Italy is an established EU carrier and its services to the US are covered by and fully consistent with the EU-US Air Transport Agreement (ATA) using 3rd and 4th freedom traffic rights between the EU and the US. Therefore, any measure to curtail or end the rights of Air Italy to serve the US would constitute a clear and serious violation of the ATA. Such action would be unprecedented and would put into question the most fundamental principles under which our aviation relations have so successfully developed over more than 10 years.”