The fight to survive the Covid-19 crisis is pitting airlines across the globe against their grounded customers. Regulations in the U.S. and Europe generally call for carriers to offer passengers a refund if a flight is canceled, with exceptions for circumstances like bad weather. It happens in normal times, but country lockdowns have dissolved schedules for weeks, with airlines parking their fleets and guarding their cash as revenue withers. Their customers are flooding Facebook and Twitter to complain they can’t get their money back for canceled trips. Tamara Watts, from Northumberland, England, said she was due to fly to the U.S. for a family road trip through California, Nevada and Arizona, before jetting to New York and then home. With the pandemic spreading, the flights were canceled by the Dutch arm of Air France-KLM.