A blimp.

Blimps are a large non plane enemy in WDL WarJetz

Description: they are a large, dark grey blimp, with a WDL logo on the sides.

they never move, they just float above the arena waiting to shoot at nearby aircraft. They are a common enemy and are found on most maps.

Armament: They are armed with a single slow firing heavy cannon, possibly 75mm

They are tough to destroy and anoying, especially if your aircraft isn't particulary durable,

Their single cannon can kill a dragonfly in about 2 shots, though they are slow firing and easy to avoid if you keep moving.

One of the missions for the flying tigers involves destroying several blimps.

Oddly the projectile from the blimp seems to come from a the center of it, rather than from one of it's actual turrets.