Berlin's new airport welcomed its first passengers on Saturday, putting an end to nine years of delays that had become a source of embarrassment for the German capital.
Flights by Easyjet and Lufthansa brought the first passengers to the new terminal of BER, the three-letter code designating the airport.
Both planes landed on the northern landing strip four minutes apart, and not in parallel on different strips as had been originally planned, due to weather conditions.
"Finally we can put our airport into service. Finally," said BER chief Engelbert Luetke Daldrup.
The airport's opening was pushed back six times due to several setbacks and gaffes over the course of its 14 years of construction, with its budget roughly tripling to 5.96 billion euros ($A9.90 billion).
Berliners frequently joked it would never open at all.
In 2012, BER's launch was canceled four weeks before the inauguration date due to issues with its fire safety regime, which uncovered other defects that led to another eight years of works.
"The time of jokes about BER has to end now," German Transport Minister Andreas Scheuer said at the opening.
Environmental activists protesting against the new airport seemed to think otherwise.
Dozens of demonstrators dressed up as penguins and marched to the new terminal to raise awareness about air traffic's impact on climate change. Some lay down in front of the terminal, blocking the entrance and holding signs that said "Cool birds stay grounded."
Several people managed to climb onto BER's roof, two of them lowering themselves down on ropes. One activist unfurled a banner saying "Stop flights, don't wreck climate."
Meanwhile, members of the group Extinction Rebellion glued themselves to a plane at Berlin's former Schoenefeld airport, which has been rebaptized as BER's Terminal 5. Police later removed the protesters from the plane bound for Istanbul, and it took off shortly after.
Opening 30 years after the Berlin wall fell, BER is intended to overhaul the city's aging air transport infrastructure.
The pandemic has, however, clouded the airport's launch and added to spiraling costs for its state-backed operator.
Only Terminal 1 was launched on Saturday; a recently finished Terminal 2 will not be needed initially after passenger numbers plunged to just 20% of the 100,000 flyers that usually pass through Berlin's airports daily.
The operator is getting an additional 300 million euros from federal and state governments to get the airport through this crisis year, with another loan of around 550 million euros promised for next year.
Due to the economic uncertainty unleashed by the crisis, it remains unclear when the airport will become profitable.
Berlin's other airport, Tegel, located northwest of the city centre, is scheduled to close on November 8.