adopted funnel bands; others (like the B7 escort group) wore letters on their funnels. Post-war Post-war Flotillas were no longer identified by bands, but by large cast metal numbers bolted to the funnels. Flotilla leaders continued to display a large band at the top of the funnel and half leaders would carry a thin black band around the funnel. Deck codes Aircraft carriers and vessels operating aircraft have a deck code painted on the flight deck to aid identification by aircraft attempting to land. This is in a position clearly visible on the approach path. The Royal Navy uses a single letter (typically the first letter of the ship's name) for aircraft carriers and large vessels operating aircraft, and pairs of letters (usually letters from the ship's name) for smaller vessels. The United States Navy, with its larger fleet, uses the numeric part of the hull classification number (a system analogous to pennant numbers). Deck codes used by contemporary major British naval warships include: HMS Albion — AN — BK — DT HMS Ocean — O HMS Ark Royal — R HMS Invincible — N HMS Illustrious — L — Q HMS Prince of Wales — P RFA Argus — AS RFA Lyme Bay — YB RFA Cardigan Bay — CB RFA Mounts Bay — MB International pennant numbers Several European NATO and Commonwealth navies agreed to introduce a pennant number system based on that of the Royal Navy. The system guarantees that, amongst those navies and other navies that later joined, all pennant numbers are unique. The United States does not participate in this system; its ships are identified by unique hull classification symbols. Participating countries, with their assigned number ranges, include: Argentina — (D: 1x, 2x; P: 3x, 4x; S: 2x, 3x; C: x; V: x) Australia (formerly incorporated into the Royal Navy system until 1969; now uses a system based on the RN pennant number format and U.S. hull classification symbols) Belgium — (A:9xx; F: 9xx; M: 9xx; P:9xx) Denmark — (N: 0xx; A/M/P: 5xx; F/S/Y: 3xx; L: 0xx) France — (R: 9x; C/D/S: 6xx; F: 7xx; M/P/A: 6xx, 7xx; L: 9xxx) Germany — (A: 5x, 51x, 14xx; D: 1xx; F: 2xx; L: 76x; M: 10xx, 26xx; P: 61xx; S: 1xx) Greece — (D/P: 0x, 2xx; A/F: 4xx; L/S/M: 1xx) Italy — (5xx; D 5xx; F 5xx; P 4xx; 5xxx; A 5xxx; L 9xxx; Y 5xx) Kenya