The intervention of the German Air Force, called Luftwaffe, during World War II is well known by those interested in this conflict, due to the large number of works dealing about it. Much less well-known are the air forces of Germany's allied countries, although in the last years excellent works appear about these ones. Among them, perhaps the least known and treated is Bulgarian Air Force (although its more exact name would be Royal Bulgarian Air Force) because of its lesser degree of participation in the war unlike other countries like Hungary, Romania or Finland. That is the reason why Bulgarian Air Force is Germany's forgotten ally...