USAAF unit identification aircraft markings

A Boeing B-17G in the markings of the 91st Bomb Group and displaying fuselage codes, tail symbols, and 1st Combat Bomb Wing color markings
B-17G Flying Fortresses 44-46604 and 44-48676 of the 306th Bomb Group, in 40th CBW markings-RAF Thurleigh UK

USAAF unit identification aircraft markings, commonly called "tail markings" after their most frequent location, were numbers, letters, geometric symbols, and colors painted onto the tails (vertical stabilizer fins, rudders and horizontal surfaces), wings, or fuselages of the aircraft of the United States Army Air Forces (USAAF) during the Second World War.

Tail codes and markings provided a visual means of identification in conjunction with the call procedures, and later assembly and combat visual identification of units and aircraft.

These should not be confused with squadron codes and letters used in the RAF systems and areas. Those serves a different function. The purpose of these markings was to serve as call signs in the Royal Air Force (RAF) radio procedures used in the UK. Two-letter squadron codes were used to denote a squadron; some squadron codes later consisted of a letter and a numeral. An additional single letter, known as the Radio Call Letter (RCL), was to identify the aircraft within the squadron, used phonetically in radio calls. Other areas continued to use only the RCN[expand acronym] or simple numbering and lettering.

As the buildup of troops continued in the Europe, Africa, Middle East Campaign (EAME), the United States Strategic Air Forces in Europe (USSTAF) bomber formations grew and assembly necessitated better visual unit identification at greater distance.

To facilitate control among thousands of bombers, the USAAF devised a system of aircraft tail markings in 1943 to identify groups and wings. Both the Eighth and Fifteenth Air Forces used a system of large, readily-identifiable geometric symbols combined with alphanumerics to designate groups when all USAAF bombers were painted olive drab in color. However, as unpainted ("natural metal finish") aircraft became policy at the start of 1944, the system evolved gradually to one using large areas of color in conjunction with symbols or patterns of color identifying the wing and often different colors for the group.

The Twentieth Air Force, eventually operating 20 groups and 1,000 bombers, also adopted a tail identification system overseas. The other six numbered air forces fighting in the Pacific War also used tail markings within the various air forces both as group and squadron identifiers. The patterns or themes varied; some were designated at the Air Force level, some at the Command level and others down at Group or squadron level. As in Europe, geometric shapes and colors were used as were letters, numbers and variations based on the RCN or serial number last three or four digits. Some pre-war bands and stripes were reinstated.