The executive European Commission originally proposed intra-EU flights join the scheme in 2011 and all international flights from 2012.

The trading scheme is the EU's key instrument to fight global warming. It sets limits on the amount of carbon dioxide (CO2) that industry may emit. Companies buy or sell permits based on whether they overshoot or undershoot their targets.

Airlines are not currently included, however, and the United States and other countries have fought against their addition.

Lawmakers voted to increase the amount of permits that airlines must buy upfront at auction to 25 percent from 2011 and said the sector's cap should be set at 90 percent of average emissions from the period 2004-2006, tighter than the 100 percent proposed by Brussels.

The plan must now go to EU governments for potential changes and approval. It must be approved by parliament and EU ministers before it can become law.

Environment Commissioner Stavros Dimas told parliament on Monday the Commission believed a two-step approach with intra-EU flights included a year before intercontinental flights would help convince other nations that the EU scheme was workable.

But parliament members felt two dates would put European airlines at a competitive disadvantage.