Activists from the Last Generation environmentalist group staged a protest at the Leipzig/Halle Airport in eastern Germany early on Thursday morning.
German news agency DPA reported, citing an airport spokesperson, that flight operations were suspended shortly after midnight and cargo shipments were also affected.
Last Generation said the protest aimed at stopping overnight freight traffic to make it clear "that this system of destruction cannot be allowed to continue unabated."
In a statement, the group reiterated its demand to the German government to "help shape and sign a legally binding international agreement that regulates the global phase-out of oil, gas and coal by 2030."
Experts have warned that Germany will almost certainly miss its climate goal of cutting 65% of emissions by 2030.
Airport protests
Last Generation has increasingly staged protests in Germany by blocking roads and runways in a bid to influence transport policy.
Last week, members of the group halted scores of flights at Germany's largest airport, Frankfurt, and blocked the Cologne/Bonn airport, gluing themselves to the runway.
Formed in 2021, the group uses its name to highlight that its young activists consider themselves as the last generation before the Earth reaches a tipping point and collapses in a climate breakdown.