Year founded: 1934
Revenue: $13.1 Billion
Employees: 44,000Worked with Boeing to engineer more fuel-efficient aircraft.
AMID RISING concern about aviation pollution, British Airways introduced a "CO2 emission calculator" on its website, letting passengers pay to offset the carbon dioxide generated by their flights. Lufthansa recently equipped an Airbus A340 with a 1.5-ton mobile laboratory to track gases and compounds. But it is American airline Continental that's gone furthest to green operations. Besides spending more than $16 billion over the past ten years to replace its fleet with more efficient aircraft, it installed fuel-saving winglets that reduce emissions by up to 5% on most of its Boeing 737s and 757s, and reduced the nitrogen oxide output from ground equipment at its Houston hub by over 75% since 2000. Its 13 full-time staff environmentalists work with engine manufacturers, design green terminals, and track carbon emissions and chemical recycling daily. Even all the trash from company headquarters is later sorted for recyclables. --Barney Gimbel