Recon ship with advanced sensor system. Agile, quick and fragile, only lightly equipped for defense. Will do as a combat ship in a pinch. Think Scouts in Homeworld.
Heavy fighter?
All-around combat fighter, cheap and easy to produce in large quantities. The most common ship on the battlefield, popular for its low price and versatility. Carries basic fighter weaponry. Does not excel in any particular role. Think Interceptor in Homeworld.
Very Heavy Fighter?
Top-notch advanced fighter, outfitted with a wide variety of weapons. An enhanced version of the Heavy Fighter class. Effective against pretty much anything, but its additional size and weight can be a problem in frantic combat situations. Much more expensive than the Heavy Fighter. Think advanced fighters in Homeworld.
Super Heavy Fighter?
Large ship equipped with light gunboat weaponry. Has a lot of punch and can be outfitted with different weapons. Its main weakness is its size, too big even for its enhanced armor. Think Corvettes in Homeworld. I know.