What does the logo of the RAF represent?

Answer 1

A target, one can assume its a sarcastic challenge to enemy aircraft

It is called a roundel and is is a circular identification mark painted on aircraft to identify them to other aircraft and ground forces. It has been used on British aircraft, in one form or another since 1915. When the First World War started in 1914 it was the habit of ground troops to fire on all aircraft, friend or foe, which encouraged the need for some form of identification mark. At first the Union Flag was painted under the wings and on the sides of the fuselage. It soon became obvious that at a distance the St George's Cross of the Union Flag could be confused with the Iron Cross that was already being used to identify German aircraft. After the use of a Union Flag inside a shield was tried it was decided to follow the lead of the French who used a tricolour Cockade (a roundel of red and white with a blue centre). The British reversed the colours and it became the standard marking on Royal Flying Corps aircraft from 11 December 1914 The Royal Naval Air Service meanwhile used a red ring with a white centre until they too standardised on the same roundel markings as the RFC.

Answer 2

Its a target one can assume its a sarcastic challenge to enemy aircraft