Dozens of international and domestic flights operated by Spanish flag-carrier Iberia were disrupted on Saturday by a problem in the company's booking and boarding system, the airline said.
Five flights - to London, Lisbon, Vigo, Barcelona and Jerez de la Frontera in southern Spain - were cancelled, a spokeswoman for Iberia, part of International Consolidated Airlines Group, said.
"At 11.30 a.m. the delays have been up to an hour in flights in Spain and Europe. It has affected dozens (of services)," the spokeswoman added. "It is centred on Madrid but also affects other airports. We have volunteers working to solve the problem as soon as possible."
"Due to an incidence in our systems, booking and boarding services have been stopped at several airports," Iberia tweeted.
"The entire Iberia team is working to solve it. We apologise to our customers for the inconvenience that the situation is causing."
It did not give any further detail about the nature of the problem or when it was likely to be resolved.
(Reporting by Graham Keeley; Editing by David Holmes)