Fortis Watch Aviatis Flieger Professional Chronograph 705.21.11 L.01. Fortis has been one of if not the best and most authentic manufacturers of pilots watches since forever. And thats not just what Fortis itself says, plenty of flying squadrons and pilots around the world confirm this, stating that the watches from the Aviatis Collection are their day to day companions. Following the long lasting predecessor model, the 597.11.11 Fortis Flieger Classic Chronograph, real fans can now rejoice in the more than worthy successor, the 705.21.11 Fortis Flieger Professional Chronograph.