Berliners voted to keep the historic Tegel airport open even after a new international hub is completed, creating a headache for the German capital’s government, which wanted it closed.

Tegel sprang up in just 90 days in 1948 to support the Berlin Airlift, a huge operation to ship supplies and thwart a Cold War Soviet blockade. It is much-loved by many Berliners and business travellers for its proximity to the city center.

Berlin’s government will now have to rethink its plans to close Tegel after some 56 percent of voters supported the non-binding referendum on Sunday, the same day as Germany’s federal election, to reconsider the proposal.

This had envisaged the closing of Tegel six months after the Berlin Brandenburg International (BER) airport – a grand project bedeviled by repeated construction and planning problems – finally starts operating. It still has no fixed opening date.

Michael Mueller, Berlin’s mayor said the result created a “very, difficult situation” and told rbb radio he would now talk to the airport’s state owners about taking a different approach that could be “legally and financially challenging.”

The chief executive of Berlin Airport, Engelbert Luetke Dalderup, said it was up to the airport’s owners to decide and that the operator was working on its aim to complete the construction work for BER by August 2018.

Opponents argue that Tegel, with its concrete, hexagonal terminal that dates back to the 1970s, is antiquated, does not meet current safety standards and must be renovated at a cost of at least 1 billion euros ($1.2 billion).

They want the state government to go ahead with plans to convert the site into a new business and technology park to boost Berlin’s economy, and build affordable flats to alleviate a housing shortage.

Supporters, however, say that even when complete the new airport will be too small to meet passenger demand and want Tegel retained to serve around 10 million passengers per year, mainly on short-haul flights.

Airlines were also divided, with Ryanair calling for it to be kept open to avoid a capacity crunch, and Lufthansa saying it would prefer to operate from one airport.

Ryanair, which placed posters around Berlin urging locals to vote to keep Tegel open, on Monday welcomed the result and called on the government to explore all options to keep it open.