In 2008, Virgin Atlantic became the first airline to test the use of biofuels on a commercial flight (albeit with no passengers on board). In 2009, Continental became the first American airline to do the same thing. On January 7th, the airline conducted the first sustainable biofuel demonstration on a two-engine aircraft. The two-hour test flight took place in Houston, where the company is headquartered. One of the aircraft’s engines was powered by 50 percent regular jet fuel and 50 percent of a special fuel blend derived from algae and jatropha, a weed that produces oil-bearing seeds.