The cap-and-trade legislation would put a price on each ton of pollution and allow businesses to buy and sell permits for their emissions. Airlines have opposed it because they say it would amount to a tax on fuel-intensive industries.

United also lobbied Congress on so-called passenger bill of rights proposals, aimed at guaranteeing passengers on grounded planes get food, water and a chance to get off the plane.

Airlines have opposed those bills because of worries that they would further complicate matters when a plane is stuck on the ramp.

United also lobbied on a bill that would raise, six-fold, the number of flying hours an entry-level airline pilot must have. It's aimed at strengthening pilot qualifications at regional airlines, and was prompted by the crash of a regional jet near Buffalo, N.Y., on Feb. 12. The bill passed the House on Oct. 14, and a companion bill has been introduced in the Senate.

The Air Transport Association, which represents most major carriers, has said it would like to see the bill refined.

Another bill that got United's attention is aimed at preventing price speculation in energy trading markets. Airlines blamed the so-called speculation for last year's run-up in oil prices, and, along with it, jet fuel prices.

Besides Congress, United lobbied the Transportation Department and White House in the July-September period, according to the form filed Oct. 20 with the House clerk's office.