European Union transport ministers have agreed to reopen portions of European airspace to airline flights, providing some relief to travellers stranded in Europe because of ash spreading from the volcano in Iceland.

The ministers agreed Monday to carve the airspace into three zones based on danger levels: a safe zone to be open to all flights, a "caution zone" to be open to some flights, and a third zone that will be closed to all flights. The zones are defined by the European air traffic control agency Eurocontrol.

Flights in the caution zone will be "very secure" with many tests on engines, said Jean-Louis Borloo, the No. 2 French cabinet official.

"We should see more planes starting to fly" by Tuesday morning, EU Transport Commissioner Siim Kallas said after a videoconference with EU transport ministers and industry officials.

The ash, which limits visibility and can damage a plane's engine, is spewing from a volcano under Iceland's Eyjafjallajokull glacier that erupted last Wednesday for the second time in less than a month.

The ash has billowed across the United Kingdom and parts of Europe, forcing officials to ground thousands of flights and stranding millions of passengers.

The prolonged closure is costing airlines at least $200 million in lost revenue daily, according to Giovanni Bisignani, the director general and CEO of the International Air Transport Association.

Of that, Canada's air travel industry is losing up to $4 million daily, according to airline analyst Robert Kokonis. He calculates that Air Canada could be losing about $3 million per day and tour operator Air Transat close to $750,000.

Some flights resuming

Less than one-third of flights in Europe were taking off Monday — between 8,000 and 9,000 of the continent's 28,000 scheduled flights, according to Eurocontrol.

Spain offered on Monday to let Britain and other European countries use its airports as stopovers to get tens of thousands of passengers stranded by the volcanic ash cloud travelling again.

In Germany, the aviation authority announced that 50 Lufthansa flights would be allowed to fly into the country using visual flight rules, while in Britain, flight restrictions are expected to be lifted over Scottish airspace by 7 a.m. local time on Tuesday. Other British airports expected to open later in the day.

Airports in Norway, Sweden and Finland were also expected to open to a limited number of flights Monday.

Stranded passengers sleep on camp beds provided by the operator of Frankfurt airport on Sunday. (Johannes Eisele/Reuters)

The cancellations have left an estimated 750,000 people stranded across Europe, Bisignani said, including hundreds of Canadians.

More than 200 Canadians stranded in London turned up at the Canadian high commission Monday for help with everything from finding prescription drugs to receiving priority status in order to return to Canada as soon as possible for medical treatment.

Britain sending ships

In a bid to help stranded travellers, British Prime Minister Gordon Brown said Monday that two naval ships are being sent to Europe to help Britons return home.

Brown said aircraft carrier HMS Ark Royal and assault ship HMS Ocean will be sent across the English Channel to meet travellers. A third ship may also be deployed.

He said Britain is also speaking with Spanish authorities to see if arrangements can be made for British travellers to fly to Spain — where airspace is still open — and then travel home by land or sea.

Canada has made no similar plans, according to Catherine Loubier, a spokeswoman for Foreign Affairs and International Trade Canada.

Officials "in Ottawa, in Reykjavik and in other Canadian embassies in Western Europe are closely monitoring the volcanic eruption in Iceland," Loubier said. "We stand ready to provide consular assistance to Canadian citizens as required."

Volcano still erupting

Meanwhile, the volcano in Iceland is still erupting, producing less smoke but bubbling with lava and throwing up chunks of molten rock. Scientists who are monitoring the mountain's explosion warn the eruption is not finished, and may still set off other eruptions at nearby volcanoes.

Geologists saw a red glow at the bottom of the volcano, suggesting the eruption is turning to lava flow and that there is less ice in the crater, which would reduce the plume.

"We hadn't seen that before," said Kristin Vogfjord, a geologist at the Icelandic weather office.

With files from The Associated Press