As “flight shaming” gains steam in Europe, Delta Air Lines CEO Ed Bastian said concern about the environmental impact of air travel is increasingly coming to the United States. “Environmental stewardship is the existential threat to our future ability to grow. There’s no question about that,” Bastian said at the company’s investor day Thursday in Atlanta. He spoke in response to a question from Cowen analyst Helane Becker about backlash in Europe and the prospect of governments raising taxes on airlines to discourage expanding tourism. “You see it happening in Europe,” Bastian said. “It’s increasingly coming here to the U.S.” Airlines account for about 2.5 percent of carbon dioxide emissions. But as more people travel around the world, the demand is driving airline industry growth — and growth of the industry’s carbon footprint globally that is outpacing gains in fuel efficiency. To view the full article visit AJC.