BERLIN (AP) — Germany’s second-biggest airline, Air Berlin, says German authorities have refused to grant permission for 34 codeshare flights with partner Etihad this winter, a decision it says it will challenge.

Air Berlin said Friday that the decision by the Federal Aviation Office “shakes the confidence of our passengers” and noted permission had been granted for the same codeshares in previous timetables. Transport Ministry spokesman Ingo Strater said the decision was based on aviation agreements between Germany and the United Arab Emirates.