Uzundzhovo Air Base (or Haskovo Malevo Airport) used to house a fighter air regiment and after its disbandment became a squadron of the 19th Fighter Air Regiment (HQ at Graf Ignatievo). When the 19th FAR was transformed into 3rd FAB and shifted to ADC Uzundzhovo went along as an independent unit: the 4th Fighter Air Base. Shortly afterwards it changed tasks and hats transferring to the Tactical Air Command as 21st Fighter-Bomber Air Base and finally disbanded.