Lufthansa spokesman Jan Baerwald said the planes, scattered around the world, would start getting ready "right now." The first flights will be from the Far East, with others following from Africa and North America, he said.
The planes will fly to Frankfurt, Munich and Duesseldorf, he said, adding that "we have an exception that allows us to fly so-called visual flight rules."
Baerwald noted that air traffic control is still keeping its restrictions on German airspace.
The ash cloud emanating from an Icelandic volcano has crippled air travel across wide swaths of Europe, stranding hundreds of thousands of passengers and costing the airline industry hundreds of millions of dollars.
With frustration growing, airlines have been pushing authorities to lift the blanket restrictions imposed by EU governments. The chief of British Airways said flights have proven that the restrictions are unnecessary.
BA chief Willie Walsh said Monday the airline's assessment is that "the risk has been minimal" and called for new government policies to get planes back in the air.
Walsh said airlines are in the best position to determine whether it is safe to fly and that the BA test flight Sunday - along with other airlines' flights in the ash cloud - "provides fresh evidence that the current blanket restrictions on airspace are unnecessary."
In Iceland, meteorologists said eruptions from the volcano and the ash was no longer rising to a height where it would endanger large commercial aircraft. British Transport Secretary Andrew Adonis confirmed there was been a "dramatic reduction in volcanic activity."
Video still showed smoke billowing into the air from the volcano under the Eyjafjallajokull glacier.
As airline losses spiraled over $1 billion, Eurocontrol, the air traffic agency in Brussels, said 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. Airports in southern Europe were open, however, and Spain offered to become an emergency hub for the whole continent.
European airlines are seeking financial compensation for a crisis that is - and by some estimates up to $300 million a day. The BA airline chief said test flights had proven that flying was safe.
As pressure mounted from airlines, European civil aviation authorities were holding a conference call Monday about what steps could be taken toward opening airspace.
"It's embarrassing, and a European mess," said Giovanni Bisignani, chief executive of the International Air Transport Association. "It took five days to organize a conference call with the ministers of transport and we are losing $200 million per day (and) 750,000 passengers are stranded all over. Does it make sense?"
The IATA, world's leading airline industry group, expressed its "dissatisfaction with how governments have managed it, with no risk assessment, no consultation, no coordination, and no leadership." The group urged governments to more urgently "focus on how and when we can safely reopen Europe's skies."
Several airlines have run flights over the last few days, and none reported problems or damage, prompting some to wonder whether governments had overreacted to concerns that the microscopic particles of ash could shut down jet engines.
British Airways said it had flown a plane Sunday through the no-fly zone and found "no variations in the aircraft's normal operational performance."
"The analysis we have done so far, alongside that from other airlines' trial flights, provides fresh evidence that the current blanket restrictions on airspace are unnecessary," BA chief executive Willie Walsh said Monday.
KLM Royal Dutch Airlines said it had flown four planes Sunday through what it described as a gap in the layer of microscopic dust over Holland and Germany. Air France, Lufthansa and Austrian Airlines also sent up test flights, although most traveled below the altitudes where the ash has been heavily concentrated.
With airlines pressing for a restrictions to be lifted, a senior Western diplomat said Monday that several NATO F-16 fighters had flown through the ash cloud, and one had suffered engine damage from glasslike deposits - evidence that the danger from the cloud is very real.
The official declined to provide more details on the military flights and spoke on condition of anonymity due to the sensitivity of the information.
Some smaller airports reopened Monday but authorities in Britain, France, Germany, and the Netherlands - home to four of Europe's five largest airports - said their air space was still closed. Britain said it was keeping flight restrictions on through early Tuesday while Italy briefly lifted restrictions then quickly closed down again.
Eurocontrol said Monday that southern Europe was mostly open for flights - including Portugal, Spain, parts of Italy and France, the Balkans, Bulgaria, Greece and Turkey - as were parts of northern Europe like Norway.smo
In London, Prime Minister Gordon Brown said the aircraft carrier HMS Ark Royal and assault ship HMS Ocean would be . A third ship is being spent to Spain to pick up soldiers trying to get back to Britain after a tour of duty in Afghanistan.
"I expect Ocean to be in the Channel today. I expect the Ark Royal to moving towards the Channel later," Brown said after meeting with the government's emergency committee, known as COBRA.
He said Britain was speaking with Spanish authorities to see whether Britons stranded overseas could be flown there and then taken home by boat or bus.
Brown said the ash cloud had created "the biggest challenge to our aviation transport network for many years."
In Spain, all airports were open Monday and the government volunteered to become the new hub of Europe to get stranded passengers moving again. Infrastructure minister Jose Blanco said Spain could to take in around 100,000 people under the new emergency plan, which focuses on aircraft trying to bring Britons home from Asia, Latin America and North America.
Spain will also beef up train, bus and ferry services to get travelers to their destinations, he said.
Tensions boiled over at Incheon International Airport in South Korea, where 30 frustrated passengers blocked a Korean Air ticketing counter and demanded officials arrange travel to anywhere in Europe after hearing about the test flights. Some complained about sleeping on airport floors and only getting one food voucher a day - for McDonald's.
"We need a flight, we need a time," Thierry Loison, who has been stuck at the airport since Friday, told Korean Air officials. "We were like animals this morning."
Transport ministers from Britain, Germany, France and Spain were meeting Monday by videoconference and will later be joined by all 27 EU transport ministers, said French Transport Minister Dominique Bussereau.
"We will try to outline corridors, if we can, based on the evolution of the cloud, to allow the reopening of as large a number of flight paths as possible, as quickly as possible and in good security conditions," Bussereau said.
Diego Lopez Garrido, state secretary for EU affairs for Spain, which holds the rotating EU presidency, said "now it is necessary to adopt a European approach" instead of a patchwork of national closures and openings.
Ash and grit from volcanic eruptions can sabotage a plane in many ways: the abrasive ash can sandblast a jet's windshield, block fuel nozzles, contaminate the oil system and electronics and plug the tubes that sense airspeed. But the most immediate danger is to the engines. Melted ash can then congeal on the blades and block the normal flow of air, causing engines to shut down.
"There is currently no consensus as to what consists an acceptable level of ash in the atmosphere," said Daniel Hoeltgen, a spokesman for the European Aviation Safety Agency. "This is what we are concerned about."
Scientists say because this volcano is located below a glacial ice cap, magma is being cooled quickly, causing explosions and plumes of grit that can be catastrophic to plane engines, depending on prevailing winds.
Geologists in Iceland saw a red glow at the bottom of the volcano, suggesting the eruption is turning to lava flow, and said there is less ice in the crater, which would reduce the plume.
"We hadn't seen that before," Kristin Vogfjord, a geologist at the Icelandic weather office, said Monday.