Boeing last week admitted that its new high-speed plane, the Sonic Cruiser, would burn more fuel than other airliners, but appeared to dismiss concerns about the plane’s environmental impact. “There is plenty of fossil fuel still around,” said Harry Stonecipher, the company’s vice chair. He tried to poke fun at Boeing rival Airbus for jumping on the environmental “bandwagon” at the Paris Air Show. Airbus said its new plane, the A380 superjumbo, would carry at least 555 passengers and use 35 percent less fuel per passenger than the Sonic Cruiser, which may seat as few as 100 people. In a letter sent on Friday, the European Union’s environment commissioner, Margot Wallstroem, lashed out at Stonecipher for his remarks.