A trade frigate was a type of starship connected to the Galactic traders. When the Galactic Empire began its assault on the Aquilaean system, every trade frigate was held on Alderaan, and their captains along with their first officers, were taken to the Ministry of Transport. To guarantee the guild's support for his planet against the Empire, Kayos, the King of Aquilae, needed the use of these frigates.
The initial and subsequent drafts for Episode IV featured the same scenes involving trade frigates. However, in the first draft, these ships were seized at Granicus, and Aquilae was originally called Townowi.