Sao Paulo’s Guarulhos International Airport, where work on a new terminal is on a tight schedule.

International airlines are worried the Brazilian government may hit them with a flurry of fines during the World Cup over delayed flights and lost bags at already overcrowded airports, the head of a global airline association said.

Less than four months before kickoff, Brazil’s busiest airport, in Sao Paulo, is still racing to finish a new terminal and other airports are preparing temporary tents to receive the influx of passengers.

That leaves airlines wary that they will be on the hook for untested baggage handling systems and overcrowded terminals. Many of Brazil’s biggest airports are running beyond capacity after years of neglect by state operator Infraero.

“It’s very unfair to hold the airlines responsible for every disruption that happens if frankly it’s a problem of the infrastructure,” said Tony Tyler, head of the International Air Transport Association, ahead of a visit Sao Paulo’s Guarulhos International Airport.

It is going to be challenging and people are going to have to be understanding

His concerns underscore the challenges facing Brazil’s aviation industry during the tournament in June and July, which Tyler called the “Aviation Cup”. Airlines are adding hundreds of international routes and nearly 2,000 new domestic flights to ferry some 600,000 foreign fans and millions of Brazilian tourists between the dozen cities hosting matches.

Yet work on chronically overcrowded airports is even further behind schedule than the construction of new soccer stadiums for the tournament, which have drawn more ire from organisers as they missed deadlines and ran over budgets.

“It is going to be challenging and people are going to have to be understanding,” Tyler told reporters in Sao Paulo. “This is why we’re a bit concerned about the very strict regulations that apply in Brazil.”

Depending on the length of a delayed flight, airlines in Brazil are responsible for food, transport and accommodations for passengers, regardless of what caused the delay. Blizzards in the United States, by contrast, can lead to cancelled flights without airlines footing the bill, said a spokesman for IATA. The scarcity of affordable hotel rooms during the World Cup could make the cost of a cancelled flight even more daunting, said Tyler.

The IATA delegation spent Thursday afternoon at Sao Paulo’s Guarulhos International Airport, where work on a new terminal is on such a tight schedule that airlines worry they will have no time to test a new baggage handling system, which is crucial to smooth operations.

Brazil’s domestic airlines and the busiest international carriers have declined to move operations into the new terminal before the tournament.

Fewer than a dozen foreign airlines are expected to move in by June, many with just a couple flights per day. Those that do may fall back on ad hoc baggage handling solutions, said Tyler.

“I think baggage is going to be a challenge,” he said. “It will be made to work ... even if it means throwing people at processes that in due time will become properly automated.”