The Wing Commander pennant originates from the days of the RFC (Royal Flying Corp) as far back as 1917 when the British Army approved the use of a small flag on the RFC Commander’s car. Over time this small command flag has become known as the pennant.
When the RAF was formed they continued this tradition and also extended it to all officers of Squadron Leader or above. In modern day use they are added to the COs jet of a Squadron, usually alongside his or her name.
19(R) Sqn Hawk displaying the pennant
11 Sqn Typhoon displaying the pennant
1(F) Sqn Harrier with the pennant
IV(AC) Sqn Harrier 95th year special tail with the pennant