Walking stick on international flights

Security is governed by TSA and the Vienna airport security authorities, not the airlines. That said, I think no one on this forum would feel comfortable answering this question at the risk of you losing your well-loved stick.

I suggest contacting the airlines for guidance on the local regulations and how they would interpret them.

If you would be upset if you lost this stick why not leave it at home and bring another one?
They aren’t particularly expensive and if you bought a folding one it would be even more convenient when you travel. 55” is quick tall would it fit in an overhead locker?

I have flown a number of times with a stick and have never had any problems. From memory the stick had to be examined/scanned and I have been provided with a temporary stick to walk through the scanner.
I don’t have specific experience of airport security in Germany or Austria but my guess is they have better things to do than confiscate a stick to make a political point.

Agee with the better safe than sorry perspective. Buy a folding cane on Amazon that you don't mind loosing. Keep your keepsake at home.

Since you are flying direct from Denver to Munich, no German is going to look at your bag from a security perspective. Only TSA will in Denver. From Vienna, as you noted, it will be Austrian security and then TSA again in Newark.

BTW, when you fly in the US, how do you get a 55" stick into the overhead?

I got tired of having my luggage opened to examine my foldup hiking poles, so started going through securty with them. Only time I had a problem was in Vancouver, where they demanded I check them (we don't check any baggage). The agent suggestged that maybe they weren't hiking poles after all but rather "mobility devices." So, now I leave my hiking poles at home and take my "mobility devices." They have metal tips, incidentally.