German flag carrier Lufthansa said Monday it had received special permission to fly 15,000 passengers home from Asia, North and South America and Africa who were stranded due to the volcanic ash cloud over Europe. A spokeswoman for Lufthansa, Europe's biggest airline in terms of passenger numbers, said 50 long-haul flights were given 'exceptional permission' to land in Frankfurt, Munich and Duesseldorf on Tuesday from destinations around the world. She stressed the flights were exceptions and 'not a return to normal flight service'. Meanwhile Germany's number two airline, Air Berlin, said it had been able to conduct one flight Monday, arriving in Munich from the Spanish holiday island Majorca, and was resuming with official permission some domestic flights. Germany's DFS air safety agency extended to 2:00 am (0000 GMT) Tuesday the shutdown of its airspace because of volcanic ash from Iceland. The decision sparked a furious reaction from airlines, which fear the crushing economic impact of the ongoing paralysis in international air travel, and have called the restrictions excessive. 