Irregular mail-plane service from Sofia to Varna was held between 1919 and 1920 and it was not until 1947 that a permanent airline between the two cities was established.
Entre 1919 e 1920 houbo un servizo de correo irregular entre Sofía e Varna e non sería ata 1947 cando se estableceu unha liña permanente entre as dúas cidades.