The European Commission is currently studying three options for dealing with aviation emissions -- inclusion in emissions trading, a fuel tax or extra ticket charges.
"It is the most probable to be approved -- to be proposed and approved," EU Environment Commissioner Stavros Dimas told a news conference, referring to the inclusion of aviation in the EU's emission trading scheme.
But he said airlines were unlikely to join the landmark system by 2012, when the first time period covered by the climate change treaty known as the Kyoto Protocol ends.
"It will be difficult to do it before, but we shall try."
The EU launched its emissions trading system in January. The scheme sets limits on the amount of carbon dioxide (C02) energy-intensive installations like power plants can emit and allows them to buy or sell allowances that give them the right to release the main gas blamed for global warming.
European airports and some major airlines -- including British Airways -- have come out in favour of an inclusion in the system, saying it would be more beneficial to the environment than a tax.
The Commission's report on aviation is due in June or July, Dimas said, and a final decision would not be made until then.
The EU executive is also considering adding other gases and other sectors to its system. It will review the scheme next year, but officials say there will likely not be time to make major changes -- which must get approval from other EU bodies -- in time to be included in the 2008-2012 trading period.
Twenty-four EU countries have their national allocation plans for the current 2005-2007 emissions trading period approved. Dimas' home country, Greece, will see its plan approved by the end of June at the latest, he said.
CALL FOR G8 CLIMATE ACTION PLAN
Dimas said emissions trading and similar measures would be the best vehicles for the world to fight climate change, but he said a global scheme based on the EU example would take time.
"Emissions trading will be the best way to get cost efficient reductions all over the world. And at the same time it will create business opportunities ... (and) jobs in developing countries while helping reduce emissions in these particular countries."
Dimas said he saw some increased flexibility from the United States, which pulled out of Kyoto, on the issue of climate change, but he said the US emphasis on technology was insufficient.
"The United States is insisting on technology -- research and technology -- which are very important," he said. "This is not enough."
Dimas said he hoped the G8 group of industrialised nations would come up with a concrete action plan to deal with climate change. Prime Minister Tony Blair has made the issue a key theme of Britain's G8 presidency.