Are you talking about size or classification?
Here's what I think how it should be:(by classification)
ratings: 1-5 (compared to size)
cruiser - small warships built for escort ( aprox. size <300m)
hull - 4, anti-cap - 3, speed - 5, aaaf - 5
corvette - fire support ships, usualy no fighters (size < 800)
hull - 4, anti-cap - 3or4, speed - 4, aaaf - 3
frigate - large fire support ships, usualy no fighters (size <1000)
hull -5, anti-cap - 5, speed - 4, aaaf - 2
destroyer - cross between a carrier and a real warship( s<2500)
hull - 4, ant-cap - 4, speed - 3, aaaf - 3, fighters - 3
battlecruiser - no fighters, built for anti-capship battle(size <3000)
hull - 5, anti-cap - 5, speed - 3, aaaf - 3
dreadnought - big versions of a destroyer (size < 6000)
hull -4, anti-cap - 4, speed - 2, aaaf - 2, fighters -3
battleship - pure warship, built to stand alone (size, aprox. 7000)
hull - 5, anti-cap - 5, speed -2, aaaf - 4
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Carriers come in diferrent sizes (from small support carriers to the big heavy carriers) Common stats for all of them are:
hull - 3, anti-cap - 2or3, speed - 4, aaaf - 2, fighters - 5
NOTE: tis stats are compared to ship size - that means that a destroyer, alltough bigger than a corvette has aprox. the same firepower becoause it carries fighters ( and they require TONS of space. That space, on a corvette is used for more armour, more firepower...)
Small ships:
Transports
Dropships
bombers
gunboats - heavy fighters (with turrets)
heavy fighters
light fighters