Sit down in an airport main concourse today and you’ll catch a glimpse of what makes the modern world tick. On a personal level, families reunite and adventures begin amid the swirl of our rapidly globalizing world. As for technology, one witnesses a marvel here as we conquer the skies. Denver International Airport (DIA), one of the largest (it covers 54 square miles) and fifth busiest airport in USA (in 2013, 25.5 million people passed under its unique tented roof), was the first U.S. airport to develop a comprehensive plan to manage environmental impact and the first to meet national and international sustainability standards. DIA marked another first when it earned membership in the Environmental Protection Agency’s Performance Track for excelling in protecting human health and the environment. Meanwhile, the Colorado Department of Public Health has recognized DIA for 10 years running as a Colorado Environmental Gold Leader for voluntarily going beyond compliance with state and federal regulations and for its continual environmental improvement. Throughout these efforts and accolades, natural gas vehicles have been a key component of sustainability efforts at the airport. Using compressed natural gas (CNG) in DIA’s 221 natural gas vehicles saves more than $135,000 each year in fuel costs. Based on the savings and overall success, the airport plans to add 25 to 50 more natural gas vehicles soon. “We continue to invest in initiatives that reduce our carbon footprint and are financially viable, which assures their perpetuity even in times of economic downturn,” said airport CEO Kim Day. “Natural gas is a key part of our energy portfolio, as it provides a lower-cost and more environmentally friendly solution for many of our operations.” Airport leaders recognize that DIA is not alone in a growing reliance on natural gas– other members of this little city, passengers, also may rely on the clean energy to power their vehicles. DIA provides public access for compressed natural gas fueling at rental car fueling stations. One gallon equivalent of natural gas is a little less than one-half the cost of one gallon of diesel fuel, so the cost savings are significant. CNG burns much cleaner than other fuels. CNG vehicles are better for the environment. Users’ experience with CNG buses has been positive and they would certainly consider using more of CNG technology for future vehicles at the airport.