Would aircraft carriers still be constructed without the treaty system?
Short answerYes. Carrier programs including Hermes, Hosho, Eagle, Furious, and Langley were already underway.
NotesCarrier development already had several practical examples before the treaty system began. Hermes, Hosho, Eagle, Furious, and Langley are cited as ships whose work was already underway. Removing the treaty therefore changes subsequent design choices without removing the existing carrier programs.