The Navigator is Lincoln's flagship vehicle,and has all the elements that Town Car buyers love (body-on-frame,rear-wheel drive,V8 engine) as well as the added benefits of a dominant driving position and four-wheel-drive capabilities. The Navigator has far more presence than any other Lincoln product and its interior is one of the most handsome to be found in the Premium SUV category. Still,rising fuel costs and a growing trend toward smaller,car-based crossover SUVs may spell trouble for the Navigator. Ford has already placed large incentives on the 2006 model to help keep sales robust. Should the economy slow,even larger discounts may surface before year's end.