By Roger Harrabin
Environment analyst, BBC News
EU ministers are poised to agree a deal on aviation that would see aircraft emissions continue to rise and possibly hand a cash windfall to the airlines.
BBC News understands the industry will be allowed to increase emissions as much as it wants by the European environment council.
Aviation is the fastest growing source of greenhouse gases.
But Europe's environment ministers look set to reject a plan for a strict cap on emissions from planes.
Instead, airlines will be given a set number of permits to pollute.
If they overshoot their limit they will be allowed to buy spare permits from firms who have managed to cut emissions elsewhere - manufacturing industry, for instance.
The ministers are expected to say this is rational, as it does not matter where emissions cuts are made - campaigners will call it a cop-out.
A UK government source has told the BBC that Europe's ministers are also likely to decide that airlines will be handed almost all their tradeable pollution permits free of charge.
When the same system was applied a few years ago in the power sector, some firms made huge windfall profits by selling on valuable permits they had never had to buy in the first place.
Lastly, it is not expected that airlines will be asked to account for the extra damage done to the atmosphere because their emissions are created at high altitude.
The decision on Thursday is not final - but it does show goverments are reluctant to curb one of the boom areas of their economy - however damaging it is perceived to be.