A European Court of Justice advocate general on 6 October will put forward an opinion on the legal challenge against the inclusion of aviation in the European Union's emissions trading system (ETS), brought forward by the Air Transport Association of America (ATA) and three of its members.
During a technical briefing today to detail the amount of free allowances aircraft operators will be entitled to when ETS takes effect on 1 January 2012, Jos Delbeke, the European Commission's director general climate action, said 6 October will be an "important moment".
The advocate general's opinion will give "a strong indication of how the court will rule", added Delbeke.
Non-compliance with ETS will result in a penalty of €100 ($135) per tonne of carbon dioxide emitted, warned Delbeke.
The US House of Representatives Transportation and Infrastructure Committee recently approved a bill that would prevent US carriers from taking part in ETS, and strong opposition to the scheme has also been voiced by China and Russia.
Delbeke said the EC is "still having intensive discussions" with various countries about ETS, and is "very open to taking those discussions forward".
He added: "We hope to have a more co-operative response by airlines and their relevant countries [to ETS]."
The EC announced today that airlines will receive 85% of their emissions allowances free of charge in the first year of ETS, dropping to 82% in the period from 1 January 2013 to 31 December 2020.
Delbeke estimates that this will result in about 380 million emissions allowances having to be bought on the market in 2012.