LONDON - The eruption of a volcano in the tiny, isolated island nation of Iceland is threatening to turn into a major headache for businesses across Europe and around the world as a spreading ash cloud closes more European airports.

Airlines are already counting the cost of grounded planes, and there are growing fears about the transportation of food supplies and other essential goods should the flight disruptions persist for several days — or longer.

But there were also some early winners from the unprecedented situation, with rail, bus and ferry tour operators all quick to lay on extra services for stranded business and leisure travelers as hotel rooms filled up.

Ryanair Holdings PLC, the leading low-cost airline in Europe, said it was extending the cancelations across most of its network through to at least lunchtime on Monday to give passengers clarity about the situation and a chance to rebook flights.

"This spreading cloud of volcanic ash is an unprecedented event in Ryanair's 26 year history, and we are continuing to work around the clock to minimise its effects on our schedules," said Ryanair Chief Executive Michael O'Leary.

Ashley Steel, global chairman for transport and infrastructure at professional services company KPMG, said that the biggest losses would come from trans-Atlantic business traffic, with the impact on economy class revenues muted by the fact that people would likely change their bookings to a later date.