From experience, OurPlane figures that its airplanes will fly around 500 hours a year. Based on that figure, after four years, the company will install a new engine and prop, upgrade the avionics, if necessary, and the owners will fly it until the end of the five-year ownership term. At the end of that time, OurPlane will sell the airplane-it guarantees a minimum of Blue Book value. It then returns the original investment to the owner, minus whatever depreciation has taken place. (If the airplane has appreciated, the owner gets that, too.) Continuing on in a new airplane after the five-year term, in my case, considering a 25 percent depreciation of my current airplane, would mean a new investment of less than $5,000.