The delayed opening of Berlin’s new international airport could cause chaos for Luft—hansa and Air Berlin, both of which are trying to minimize the potentially dramatic consequences of the deferred launch of operations.

Berlin’s airport operator, Berliner Flughaefen, today announced it will be impossible to keep the projected June 3 opening date, with CEO Rainer Schwarz attributing the delay to the terminal’s fire protection system.

That system has failed recent tests, and further testing is needed to ensure everything works properly, Schwarz said.

Schwarz did not specify how extensive the delay will be, although Berlin Mayor Klaus Wowereit said later he hoped the airport could be opened in late August. Some industry sources are more skeptical.

Airlines doubt that fire protection is the only issue affecting the current schedule. “We have had to realize over the past few days and weeks and after several tests that there is a need to act on several fronts,” says Lufthansa. And while the airline is not officially specifying the issues, company sources indicate that there is a general uneasiness concerning the state of check-in facilities at the airport.

Schwarz stressed he is ready to stay in his position “in this difficult time.” However, Matthias Platzeck, the prime minister of the state of Brandenburg, noted that the delay was “more than a bad surprise” and that he was “very angry.” He said he expects a detailed plan by management by next Monday that specifies a recovery plan and new opening date.

Brandenburg is the airport’s largest shareholder along with the city of Berlin.

Berlin Brandenburg International (BBI) is intended to replace Berlin’s two existing airports Tegel and Schoenefeld. Tegel, the city’s main airport, is operating at capacity.

BBI originally was scheduled to open in November 2011, but terminal modifications caused a delay of six months.

This latest delay is a huge blow for both Lufthansa and Air Berlin. Lufthansa has planned to increase capacity 40% from Berlin, opening 50 more destinations, and was scheduled to base six more Airbus A320s in the country’s capital and introduce a low-fare scheme to stimulate demand. Air Berlin is currently building up a six-wave hub system and introducing long-haul services.

Now the question is whether those plans have to be pushed back many months. But both carriers cannot simply cancel the additional flights; they have already sold tens of thousands of tickets and now are no longer sure whether they will be able to fly the planned schedules.

Lufthansa says it plans to stick to its schedule and is securing additional slots at Tegel. However, even if it manages to get more slots on the already busy runways, it will be a huge challenge to process the additional passengers through Tegel’s crowded terminal.

Moving part of Lufthansa’s or another operator’s flights to Schoenefeld is an alternative, although that would incur huge costs that would likely have to be covered by the airport company.

Air Berlin says it is “very disappointed,” with CEO Hartmut Mehdorn noting that “this will cause huge logistics challenges and significant additional costs that we cannot yet calculate.”