There's not much time left, but if you're in the enviable position of shopping for a new airplane, the government's bonus depreciation tax benefit ought to stimulate your personal economy to make the leap before year end. And some manufacturers are sweetening the pot even further. Diamond Aircraft will match customer down payments of up to 10 percent, and throw in Garmin Synthetic Vision Technology for free on selected models. Liberty Aerospace is offering deep discounts on eight of its factory demonstrator XL2s — selling for as little as $115,000 from list prices as high as $210,000. And Mooney is taking a page from car dealerships in the form of low-interest financing — as low as 2.99 percent with flexible leaseback options for buyers. For anyone perched on the fence, this could be the time to take advantage of greener grass on the other side of aircraft ownership. Check with your accountant and tax advisor to ensure you're financially healthy enough for airplane-buying activity.