Well, I hate to rain on everyone's parade, but Max Müller
did NOT win the Hohenzollern House Order. Gunnar is correct in pointing out that in the book "Der Flieger von Rottenburg" it states that he won it on 20 Jul 1917. However, Max was still an Offz.Stv. on this date. He wasn't promoted to Ltn. (and active at that) until 26 August 1917, and therefore he was not eligible for the HOH. I quote from Neal O'Connor's Vol. I on the Bavarian awards:
"July 1917 was marked by the receipt of one of the most unique and exclusive awards of WWI. On July 14 Prussia awarded Müller their Kreuz der Inhaber mit Schwerten (Member's Cross with Swords) of the Royal Hohenzollern House Order. This was an honor cross for non-commissioned personnel that was affiliated with the Royal Hohenzollern House Order and should not be confused with the latter which went only to officers. Only 16 awards of the Members Cross with Swords were made during the war, with ten of them going to aviators."
Immo, I haven't checked on Festner yet, but I suspect he also may have been one of the 10 mentioned above in lieu of the HOH. Germany, and Prussia in particular, was very 'picky' about awards, and if you didn't qualify or weren't eligible for a certain award, you didn't get it. Period. That was why Germany instituted the Golden Military Merit Cross for non-commissioned personnel. They were not officers and as such COULD NOT win the Pour le Merite.
Sorry guys. Rick