Air Berlin's insolvency filing has deepened the malaise surrounding the yet-to-be-openedBrandenburgairport. And the Oneworld airline's challenges and likely break-up highlight how the market has changed since the German capital's long-delayed future gateway was conceived.

FlightGlobal schedules data for August shows that theAir Berlinis, by a wide margin, the largest operator at the city'sTegelairport – representing more than 43% of total capacity in ASK terms. The airline is also Berlin's largest long-haul operator.

US carriersDelta Air LinesandUnited Airlinesboth serve New York from Berlin, which is linked to Montreal byAir Canada, Beijing byHainan Airlines, and Doha byQatar Airways, whileAir Berlin's network from the German capital spans several US cities – mostly served without competition – and Abu Dhabi, the base of key shareholderEtihad Airways.

BeforeBrandenburg's opening was repeatedly postponed,Air Berlin's plan was to build up a long-haul hub at the new airport. Now it seems likely thatAir Berlinwill not exist – at least in its current form – whenBrandenburgairport eventually opens.

What's certain is thatAir Berlinwill this winter axe the "loss-making" routes linking its home city with Abu Dhabi and Chicago, and is accelerating plans to terminate the Los Angeles and San Francisco services it operates fromTegel.

BUILDING DELAYS

When the new airport will start handling passengers remains unclear, however. The latest target of opening the terminal during the second half of 2017 was abandoned earlier this year.

The project has been plagued by delays from the outset. It was back in 1996 that the federal government and the states of Berlin andBrandenburg– the three shareholders in airport operator FBB – decided to extendSchonefeldairport's site to the south and construct new terminal facilities and a second runway for the capital's future gateway. There were plans to closeTegel,Schonefeldand the then-active Tempelhof once theBrandenburghub became operational. An opening was targeted for 2007, but the project took a decade to get approved, amid legal battles.

Construction finally began in 2006, with an opening scheduled for 2011. That target was shifted to mid-2012 as a result of new European Union security regulations requiring increased space for passenger screening facilities. But an inauguration scheduled for 3 June 2012 was cancelled by the FBB in the preceding weeks, as a result of concerns over the terminal's fire-protection system.

It's original

Multiple new target dates were subsequently set – and all abandoned as inspections and repair works over the years revealed additional areas of construction work that required modification. The terminal's flawed smoke-extraction system and automatic door controls were initially identified as central problems that prevented the opening in mid-2012. But it later emerged the building's sprinkler system, electrical wiring and IT infrastructure needed extensive rework too.

Construction work came to near-standstill in late 2012 and, two years later, FBB conceded it had been overwhelmed by the extent of required changes to the greenfield terminal. The operator said project-management changes were necessary to divide the required work into "manageable packages" and reduce complexity to a "controllable" degree.

Throughout this period, air travel demand has been on the rise and airlines have continued to lift capacity in Berlin, notably over the past two years. And it has become clear the new airport will already be too small when it opens. In 2016, the total number of passengers atTegelandSchonefeldgrew 11% to 32.9 million.

FBB saysBrandenburg's existing terminal with three piers can handle 22 million passengers a year – previously it had issued a figured of 27 million. But in recent days, the airport operator has outlined plans for boosting capacity to 55 million passengers a year by 2035.

Illustrations of its expansion masterplan indicate that in the period 2018-21, FBB intends to extend the north pier with six additional aircraft stands and to build two annexes north and south of the main terminal building. The two annexes will provide "operational optimisation" and additional baggage-handling facilities, the plan suggests.

A new, dedicated low-cost terminal – plans for which had already been disclosed – is also part of the masterplan's "Phase 0", which is set to raise capacity to 33 million in 2021.

Phase 1 – spanning the period 2022-25 – involves a second extension of the north pier with a further six aircraft stands, as well as construction of an additional passenger terminal, landside of the existing terminal complex. This will raise capacity to 45 million. The new Terminal 2 will initially be connected to the north pier and feature a "person transport system"– presumably to connect with additional car parking facilities further afield.

Phase 2 – spanning 2026-30 – will entail extension of the south pier and a connection to Terminal 2, and increase capacity to 48 million.

FBB notes that the south pier's extension will increase capacity by six million passengers and thus facilitate a 50% reduction in utilisation of the dedicated low-cost terminal – near the north pier – to three million.

As part of Phase 3, running from 2031 to 2035, FBB intends to build a satellite pier on the apron opposite the main terminal. The satellite will have an overground connection with the main complex and increase capacity to 55 million.

The operator foreseesBrandenburghandling 55 million passengers by 2040.

LOW-COST GROWTH

Unlike other German cities, Berlin has for a long time been a market dominated by low-cost carriers. BeforeLufthansadecided in 2012 to transfer all non-hub traffic to budget unitGermanwings, the airline was contemplating setting up a local low-cost operation in Berlin to compete with the likes ofRyanairandEasyJet.

Today, those two budget carriers together represent nearly three-quarters of ASKs fromSchonefeld, FlightGlobal schedules data shows. Since 2011Ryanairhas lifted its capacity more than sevenfold, fuelled by rapid growth over the past two years in particular since opening a base atSchonefeldin October 2015.Ryanairhas increased its Berlin capacity more than 50% in the past year and overtakenEasyJetas the largest carrier atSchonefeldwith almost 39% of the airport's capacity.

EasyJetstill provides 34.4% of ASKs fromSchonefeld. It has grown steadily at the airport and notably expanded its capacity there by 9% in the past year.

German leisure subsidiaryCondorisSchonefeld's fifth-largest carrier, in ASK terms. But theThomas Cooksubsidiary nearly halved capacity there since 2016, and represented less than 3% ofSchonefeld's total ASKs in August.

WhileNorwegianhas reduced capacity atSchonefeldover the past year, the Scandinavian budget carrier's long-term capacity at the Berlin airport has grown by a fifth since 2011. Another low-cost carrier,Wizz Air, meanwhile more than quadrupled its capacity at Schonefeld between 2016 and 2017.

AtTegel,Lufthansa's budget divisionEurowingsis the second-largest operator. But the carrier has shrunk capacity 13.6% over the past year, whileLufthansa's mainline services to Frankfurt and Munich stayed flat. Leisure carrierTUIflyis the third-biggest operator, but it has reduced ASKs 18.6% since 2016.

Air Berlin's capacity grew between 2016 and 2017 for the first time in five years. ASKs inTegelwere increased 18.6% as the carrier focused, under a 2016 restructuring programme, on scheduled services from Berlin and Dusseldorf, and started new long-haul routes from the two cities.

The airline filed for insolvency on 15 August. The German government providing a €150 million (USD 177 million) bridging loan, and negotiations aboutAir Berlin's estate are under way.Lufthansahas made an offer to acquire parts of the ailing carrier.EasyJettoo has been linked to the talks, whileRyanairhas signalled interest in a potential bid.

LONG-HAUL ROUTES

What previous airline failures in Europe – such as Hungarian flag carrierMalev's demise in 2012 orCyprus Airways' collapse in 2015 – have shown is that vacated short-haul capacity will quickly be claimed by competitors, especially budget airlines. But what will happen withAir Berlin's long-haul operations is perhaps harder to predict.

Lufthansapreviously said it would deployEurowingsfor potential long-haul flights outside its Frankfurt and Munich hubs.Eurowingsbuilt up an intercontinental operation over the past two years from Cologne, and will open a second long-haul base in Munich in 2018.

But the German group might not be the only one considering long-haul flights from Berlin.Norwegiancommercial chief Thomas Ramdahl told FlightGlobal at the Paris air show in June that the Scandinavian budget carrier was evaluating long-haul flights from Berlin, among other cities including Dusseldorf, Munich, Amsterdam and Madrid.

It seems unlikely thatBrandenburgairport will be a traditional hub for connecting short- and long-haul flights, asAir Berlinhad planned. FBB's expansion plan to build a dedicated low-cost terminal suggests thatBrandenburgwill play a different role.

Meanwhile, a referendum to be held on 24 September – the same day as German parliamentary elections – will ask Berlin's voters whetherTegelshould be kept open. Supporters of the dated but popular airport close to Berlin's city centre have secured the referendum in a bid to overturn the government's 1990s decision to closeTegeland Schonefeld when the new gateway becomes operational – andBrandenburg's long delay has worked in their favour.

Ryanairis urging voters to favour keeping the airport open. The low-cost carrier notes that if Brandenburg has an annual capacity of 27 million passengers – the figure given by FBB before the recent downward revision – this would be a level similar to that of Dublin airport, which serves a city with one-third of Berlin's population.

Dublin airport's passenger numbers reached 27.9 million last year. Irish census figures give the capital's population as 1.17 million. Berlin's, meanwhile, is 3.52 million, the city's statistics office indicates.

Schonefeld andTegelwere due to be closed when the new airport opens. But Schonefeld's end date has been pushed back to 2023 as a result of the Brandenburg delays – to which there is, still, no end in sight.