Google sponsored a green challenge in aviation called the CAFE (Comparative Aircraft Flight Efficiency) Green Flight Challenge. There were a number of aircraft entered in the competition for a chance to win some significant money. The first place prize was $1.35 million and the second place prize was $120,000. The competition was very specific in how the aircraft must perform.
The winner had to be able to fly 200 miles in under two hours and use less than one gallon of fuel per occupant or the equivalent in electricity. Both teams that won first and second places were flying electric aircraft. Both of the aircraft also achieved twice the efficiency that the contest rules stipulated. That means that they both flew the 200 miles using only slightly more than a half gallon of fuel equivalent per passenger.
Both aircraft look more like gliders meant for soaring with no power than general aviation aircraft. The money won by the first and second place teams is nothing compared to the cost to participate. The teams that entered the competition overall spent more than $4 million. The winner was Pipistrel with eGenius coming in second.