A recent flight to a conference inspired me to think about the impact of airports on our environment and society. Although modern planes have made it safe and fun to travel around the world, they use a vast amount of fuel. The petroleum used by the array of behind-the-scenes equipment, from shuttle buses to luggage carriers, adds up as well. Although Clean Cities [1] doesn't address planes, our 87 local coalitions have helped airports limit their petroleum use in other ways, reducing their smog-forming and greenhouse gas emissions.

A number of airports have adopted the use of alternative fuels and advanced technology vehicles, ranging from gaseous fuels to hybrid cars. Denver International Airport [2] has a special underground baggage handling tunnel that only vehicles running on either compressed natural gas [3] (CNG) or electricity [4] can use. Even their security force relies on electric, three-wheeled police vehicles instead of petroleum to get around. Flyers themselves experience advanced technology at the Charlotte Douglas Airport [5], which runs plug-in hybrid electric shuttles. Biofuels are the choice of other airports like the Lambert-St. Louis International Airport [6], which runs almost all of their 400 vehicles on B20, a blend of 20% biodiesel [7] and 80% diesel. All of these technologies decrease our reliance on petroleum, increasing our country's energy independence and reducing the airports' environmental footprint.

Passengers may have an opportunity to use these technologies themselves after they step off the plane. Many rental car companies offer green options, such as hybrid vehicles [8] or flexible fuel vehicles [9] that run on E85 (85% ethanol and 15% gasoline). If you rent a flexible fuel vehicle, you can use the Alternative Fueling Station Locator [10] to find E85 stations along your route. While you're on the road, you can even use the mobile Station Locator to find the five closest pumps. A few rental companies in California are beginning to offer all-electric and plug-in electric vehicles, like the Nissan Leaf and Chevy Volt. Lucky drivers that manage to snag one of these can also use the Station Locator to pinpoint electric charging stations.

If you aren't renting a car, you can still make a greener choice for your transportation. The Seattle Tacoma International Airport [11], which requires all taxis or shuttle buses to use CNG, estimates their program reduces the same amount of smog-forming pollutants that 800 passenger vehicles produce in a year. Other airports, including Boston, Dallas, and San Francisco, give preference to taxis [12] that run on compressed natural gas or use hybrid technology.

So if you're leaving on a jet plane, stop for a moment to think about all of the vehicles involved in your trip. There's a good chance some of them don't rely on petroleum, especially the ones you don't even see.

Shannon Brescher Shea is the communications manager for Clean Cities in the Vehicle Technologies Program of EERE.