The Starfish Booster has a similar profile to the Starfish. It is designed to attach to the sides of a vanship, providing additional thrust. The Starfish Booster is also capable of independent flight, allowing its pilot to leave it hovering in the air while they detach their vanship, and later return to it.
A Starfish Booster appearing in the Last Exile - Travelers from the Hourglass has unfolding arms and is equipped with machine guns. It is not yet known if the Starfish Boosters appearing in the anime also have these features. Judging from the three weapon ports in each wing from the offical pictures, it is safe to assume they do. Interestingly these weapons seem to be an upgraded starfish, having concealed thrusters, and yet the back attachment piece uses the more crude Claudia drives seen in the first season, as well as in use by the vespas, vanships, Urbanus class vessels, and the Turan naval vessels.