Deutsche Lufthansa AG will cancel almost all flights from its main German hubs in Frankfurt and Munich Wednesday because of a strike by ground crew, exacerbating the chaos that has snarled Europe’s crucial summer travel season.

Europe’s biggest airline will cancel more than 1,000 flights in the two cities, warning that the disruption may linger into the weekend, when travel is due to pick up. There’s only very limited scope to rebook passengers whose trips have been canceled, Lufthansa said in a statement.

The aviation industry is bouncing back from the depths of the coronavirus pandemic that forced Lufthansa into a government bailout and caused huge losses across airlines. But as passengers rush to board planes again for business trips and their summer vacation, they’re confronted with chaotic scenes at airports that often lack sufficient staffing to manage the surge.

Weeks of travel chaos across Europe have seen airlines and airports blaming one another for shortages and poor preparation. London Heathrow airport said Tuesday that airlines need to hire ground staff more aggressively to help overcome persistent travel disruptions, warning that a cap on flights to ease the chaos might have to stay in place for at least another year.

Waiting lines snaking out of terminals, mountains of stranded luggage and hastily canceled flights have become the scourge of European aviation this summer. In a further disruption for travelers, much of the UK’s train network is set to be shut down on Wednesday by a railway worker strike.

Profit Target

While Lufthansa had so far avoided the industrial action ensnaring rivals like Ryanair Holdings Plc, its labor unions are starting to round on management as they seek better pay. Members of Lufthansa’s pilots union are also holding a vote on whether to go on their own strike, a move that would inevitably lead to a further reduction to scheduled flights.

“The early escalation of a previously constructive collective bargaining round is causing enormous damage,” Lufthansa Labor Director Michael Niggemann said in the statement. 

The Verdi ground-crew union had called the strike due to a dispute over pay and conditions, escalating a crisis at the airline after staffing shortages led to thousands of flight cancellations earlier in the summer. Germany is in the middle of the summer vacation period, with schools closing in more federal states this week. 

Lufthansa fell as much as 0.6% to 5.98 euros in Frankfurt. The stock has lost about 3% in value this year. 

Chief Executive Officer Carsten Spohr has pledged to boost earnings before interest and taxes to a minimum of 8% by 2024, a move he said is needed to reduce debt. Disputes with worker representatives suggest Spohr might have trouble reaching those targets, as he tries to balance the need for more staff with his desire for lower costs.

Still, the airline earlier this month said it returned to profitability in the second quarter, benefiting from surging travel demand that’s forced the sector to raise fares and limit seat availability.

British Airways reached an agreement this month with check-in employees to head off a strike that had threatened to cause further disruption after the carrier scrapped thousands of flights amid its own staffing crunch.