The European Commission and consumer groups on Tuesday increased the pressure on airlines to reimburse passengers hit by air travel chaos created by the ash cloud from an Icelandic volcano.
The moves came as a change in wind direction swept the volcanic ash back towards Europe, closing down Irish airspace and threatening Britain.
"Today thousands of consumers affected by flight disruptions are still rightly clamouring for their rights to be respected in practice," said EU Health and Consumer Policy Commissioner John Dalli.
"My message to them is: do not hesitate to claim what is yours. If an airline or a tour operator continues to ignore your rights, a European Consumer Centre near you can be your next port of call," he added.
The commission, the EU's executive arm, also favours scrapping certain night flight restrictions in such cases to allow the swifter repatriation of stranded passengers, who numbered in their hundreds of thousands worldwide last month when the ash cloud shut down airspace in much of Europe.
The network of European Consumer Centres (ECC-Net), in cooperation with the EU commission, published, in all EU languages, a "practical complaint package" to help consumers claim their rights with as little grief as possible.
The one-stop package includes a standard complaint letter, and list of addresses where they could be sent along with advice on out-of-court settlement procedures for extracting compensation from unwilling airlines and tour operators.
"EU consumer rights apply even in extraordinary circumstances. In fact, talks on aiding the companies which suffered as a result of the ash crisis must be linked to their respect for passenger rights," said Dalli.
EU officials have stressed, since the travel chaos began on April 14, that stranded passengers are entitled to be reimbursed for costs incurred while waiting for replacement flights, including food and drink and hotel accommodation.
However if they accepted a cash reimboursement on the spot for their ticket then the airlines need offer no further support.
These rights must be respected by all airlines flying out of European airports, and for all flights into Europe with European airlines.
The ECC-Net website, including links to national sites and the complaints package can be found at http://ec.europa.eu/consumers/ecc/index_en.htm.