The cloud of volcanic ash which has forced countries across Europe to close their airspace is likely to cost the airline industry over 100 million euros (135 million dollars) a day, the Association of European Airlines (AEA) said Friday, according to dpa. Hundreds of thousands of would-be travellers have been left stuck at airports ahead of the weekend, which marks the end of the Easter holidays in much of Europe. The airlines which were to carry them are obliged by law to look after them. "On a normal day, our members would expect to make 200 million euros in revenues. The latest figures from (air traffic control body) Eurocontrol are that 60 per cent of intra-European flights are expected to be cancelled today," David Henderson, AES's information manager, told the German Press Agency dpa. By that calculation, Europe's airlines are likely to lose some 120 million euros in revenues on Friday alone. However, Henderson pointed out that the final cost calculation would be much more complex, as airlines were also having to take care of passengers stranded in transit. "We're starting to get reports from our members that they're spending lots of money on hotels for passengers," he said.