Okay kiddo, fleet special is when a company buys a bunch of cars all at once to use for their business. They usually get a special deal from the car companies because they are buying so many at one time.
These cars are usually pretty basic, without a lot of fancy features or decorations, because the main goal is to use them for work and not for fun.
So basically, fleet special means a big group of simple cars for a company to use for work.