Didn't fly one of the advertised flights, but business took me in an out of MUC a couple of times over the past 10 days.
Honestly, until it was pointed out somewhere in the thread I hadn't even noticed that quite a few of the women working in MUC were wearing Dirndl. You get so used to seeing them in general in Bavaria (especially around Oktoberfest) that they don't stand out. Now seeing one in Frankfurt, I would have noticed!
My intercon flights in and out of MUC were from DEN and to EWR (on Privatair) so no dirndled flight attendants.
Interestingly as to the world cup comments. I fly quite a bit around Germany and Europe then and very much remember all the "paraphenalia". This year around Oktoberfest it's not so bad although on my MUC-FRA, FRA-LIN and MUC-EWR they served an "Oktoberfest Snack Plate" which includes wurstsalat, obazda (I wouldn't even know how to translate that one - think cheese spread), krautsalat and depending on the flight either leberkaese (having to do nothing with either liver or cheese) or "frikadellen" (think cold veal hamburger patty) as well as a little chocoate with an oktoberfest heart on it. All very very traditional. On the MUC-EWR flight they even served freshly warmed brez'n!