Etihad Airways has appealed a German court’s decision revoking the approval of 29 of its codeshare flights with Airberlin. The notice of appeal was filed Jan. 4 in the higher administrative court in Germany’s Lüneburg.

The Abu Dhabi-based carrier said the German Ministry of Transport raised concerns on 29 of the codeshares last summer, based on lobbying by Lufthansa. As a result, in November it approved the 29 codeshares only through Jan. 15, 2016.

Last week, the Administrative Court of Braunschweig ruled the German Ministry of Transport was entitled to reject the 29 Etihad-Airberlin codeshares. The decision is effective from Jan. 16 through the end of the current IATA winter schedule ending March 30, 2016.

Etihad president and CEO James Hogan said in a statement: “With Airberlin, we are working to ensure that no traveler suffers as a result of this dispute, and all bookings will be honored. We will fight all the way to protect our investment, to protect our partnership with Airberlin, and to protect competitive choice in German air travel.” He said Etihad’s commitment to Airberlin was in stark contrast to the lack of support demonstrated by the German Ministry of Transport for a “proud German airline.”

In 2011, Etihad Airways took a 29.2% stake in Airberlin, following encouragement from German regional and national Government representatives. The airlines had approval for codeshare services on a total of 63 air routes. The remaining codeshares remain unaffected.

Etihad said codeshare services to international destinations that have operated for years without any concerns were being raised as pro-competitive. “That was entirely correct, given that they meet the terms of the air services agreement between Germany and the UAE—a fact confirmed not just by our own legal team and expert advisors but by a former Director General of Civil Aviation for Germany,” Hogan said.

Airberlin CEO Stefan Pichler said in a separate statement: “We are appealing against this decision because it does not serve the best interests of the traveling public. Indeed, the main beneficiary of the decision is Lufthansa. Airberlin is Lufthansa’s sole competitor in the German domestic market. We keep the competition honest, strong and effective, as otherwise Lufthansa would have a monopoly which would be disastrous for German consumers.”

Hogan said that after four years of investing in Germany, supporting Airberlin jobs and creating own new employment in Germany, “We find the rules have changed. As a global business, we focus our investments in markets which will deliver long-term returns. We were encouraged to invest in Airberlin.”

However, Hogan added that since that initial investment, the carriers have faced a series of significant challenges, including the introduction of airport taxes, which have directly eroded Airberlin’s profitability.

“In other markets, such as Australia, India, Italy, Serbia and the Seychelles, our investments have been welcomed and supported. Yet in Germany, our commitment continues to be undermined by the lobbying efforts and protectionist tactics of Lufthansa,” Hogan said.

“Unless the German government can show its commitment to support all German companies and German jobs, its reputation as a safe country in which to invest is at stake. Investors need every reassurance that the integrity of their investments in Germany will be respected and protected,” Hogan said.

He added that Etihad is but one investor in one industry. “But our experience will serve as a warning to others when it comes to making international investment decisions: Make no mistake. Protectionism will undoubtedly harm the investment landscape in Germany.”