Actually my Remos uses less than 15 l/hr. At 120mph thats about 40 mile per imp gallon. Multiply that by straightlining (robinson quote 1.5) and you are up to 60 miles per imp gallon. Thats motorbike territory and you don't hear many motorcyclists moaning about the price of gas. 150 hours of flying a year will cost me 2 starbuck coffees a day. In other words you don't even register the cost. The savings in fuel alone over 30 years is about the same as the cost of the aircraft