A German court has thrown out an attempt by Switzerland's national airline, Swiss, and Zurich airport to block the extension of a flight ban on weekends.
The ruling means that weekend flights over southern Germany will now be prohibited between 2000 and 0900.
Swiss and the airport were trying to overturn a bilateral aviation deal, still to be ratified, between Switzerland and Germany, which imposes tough restrictions on flights over German airspace.
The administrative court in Baden-Württemberg, a German state that borders Switzerland, had been expected to throw out the complaint - the latest development in a long-running dispute over noise pollution between Bern and Berlin.
Weekend flights at the airport are currently banned between 2200 and 0600.
Swiss had said certain parts of the agreement contained "discriminatory measures" and that the restrictions could reduce flight capacities between 25 and 30 per cent.
Residents in southern Germany complain of noise pollution from flights at Zurich airport, which is less than 20 kilometres from the German border.
Switzerland and Germany agreed to cut flights from 150,000 to 100,000 per year to tackle the problem.
swissinfo with agencies