Deutsche Lufthansa AG is canceling a total of 3,100 flights after a wave of coronavirus infections worsened staffing shortages, adding to Europe’s travel chaos as the crucial summer vacation period gets under way.

Germany’s flagship airline on Friday announced it will scrap 2,200 domestic and European routes in July and August, on top of 900 cancellations unveiled earlier this month. That’s around 4% of the carrier’s capacity during that period, according to a spokesperson. Lufthansa fell as much as 3.4% in Frankfurt.

Travel demand has rebounded dramatically in Europe with the lifting of virus curbs, leaving some airlines struggling to cope and subjecting passengers to hours-long queues and cancellations. A new Covid-19 outbreak—while less deadly than previous waves—is causing growing absences from workplaces, worsening acute labor shortages. 

Growing labor unrest as workers seek pay increases to keep up with inflation is adding to the problem, with strikes threatened or under way at airlines including Ryanair Holdings Plc and IAG SA’s British Airways.

The developments are a fresh blow to the European aviation industry that was among the worst-affected during the pandemic, with airlines and airports losing billions of euros after the virus burst a decades-long travel boom. Carriers cut back staffing during the health crisis and have been slow to rebuild, worried about the resiliency of ticket sales.

The Lufthansa cancellations add to disruptions at the region’s airports, which are struggling to attract ground-handling staff over pay disputes, further crimping capacity. 

A group of Czech teenagers traveling to Portugal to attend a surf camp got swept up in the chaos. Their Lufthansa flight to Frankfurt was delayed late Thursday, causing them to miss their connection to Lisbon. They spent the night in an airport hotel with no working air-conditioning and as of noon local time, were still waiting for confirmation if they could make it out on Friday.

“We were supposed to see some sea animals today, maybe dolphins,” said Jachym Sugarek, 19, sitting on the granite floor at Lufthansa’s main hub in Frankfurt. “Instead, we had black flies in our hotel room last night.”

Weekend Walkouts

More pain is coming. Ryanair workers will stage walkouts in countries including Italy, France, Portugal and Belgium, where flights are set to be disrupted Friday or over the weekend. British Airways check-in staff are set to strike at London Heathrow airport, the GMB and Unite unions said Thursday, though no dates have been set as they pursue a last-minute settlement in the pay dispute.

Airports have had to adjust their schedules as a result of the chaos. London Gatwick last week announced it would scrap hundreds of flights over the peak summer travel period—hours after Amsterdam’s Schiphol hub took a similar step—because of the deepening staffing crisis. 

EasyJet Plc, which operates many routes at those airports, said it would cap flights as a result, suffering an earnings hit of £100 million ($123 million) to £200 million. Earlier this spring, British Airways scrapped 10% of flights from its timetable through October in a move that it said was aimed at boosting “operational resilience.” 

Lufthansa, looking to a busy summer to boost sales and reduce debt, had planned to deploy 2022 capacity equal to 75% of the 2019 level. While Chief Executive Officer Carsten Spohr last month said he was “mentally ticking off the crisis” as the Covid threat recedes, the recent surge is again shaking his summer plan.