In the former Royal Naval Air Service, which was merged with the Royal Flying Corps to form the Royal Air Force in 1918, the pilots held appointments as well as their normal ranks in the Royal Navy, and they wore insignia appropriate to the appointment instead of the rank. A flight commander wore a star above a lieutenant's two rank stripes, squadron commander wore two stars above two rank stripes (less than eight years' seniority) or two-and-a-half rank stripes (over eight years seniority), and wing commander wore three rank stripes. The rank stripes had the usual Royal Navy curl, and they were surmounted by an eagle.