Climate activists from the "Last Generation" group protested on Wednesday against food waste and for a more consistent climate policy at three of Germany's biggest airports in Munich, Frankfurt and the capital Berlin.
It marks an escalation of their regular protest in recent weeks that have mostly targeted motorway slip roads.
Justice Minister Marco Buschmann, from the Free Democrats, has slammed the protests, saying previously that "unregistered demos on motorways are and remain illegal."
Green party lawmaker Jürgen Trittin expressed understanding for the demonstrators, including for their motorway blockades in recent weeks, saying to the Zeit newspaper that "civil disobedience" did not make the activists "violent criminals."
Both are members of parties in Germany's three-way coalition government with the Social Democrats, and the protests have revealed differences between the parties' perception of climate demonstrations.
In Berlin a road blockade by a group of demonstrators at the capital's airport did not cause major disruption. Four men and women stuck themselves to an access road early in the morning, but traffic was quickly diverted and the demonstrators were removed from the road before mid-morning, police said.
In the Bavarian capital, eight activists glued themselves to the road by the airport, blocking access roads to the freight area at two points. According to the Munich police, both blockages could be avoided relatively easily.
In Frankfurt six activists blocked an access road to the cargo area of the airport. They held up banners saying "Save food, save lives." There were further actions around the airport, for example on the feeder roads and intersections, a police spokesman said.
