Answer
The difference is about $20,000 and size and features. the lincoln aviator is no longer available, but has been replaced this year by the lincoln mkx which is based on a mazda 6 platform. base price is $31,000 - $38,000, comes with a 3.5 liter v6 engine, has a 6-speed automatic transmission and weighs in at about 4,420 lbs. the lincoln navigator is a larger and more expensive model and the base price is $50,000 - $56,000 comes with a 5.4 liter v8 engine, has a 6-speed automatic transmission and weighs about 6,070 lbs. the other difference is that the mkx can handle 5 passengers while the navigator can handle up to 9 passengers.