I've been on planes with my Canemaster Gentleman's Cane two weeks ago. No problems. I had to run it through the X-ray machine, as always. I have a doctor's note, though, if it got down to that, plus I can show them the orthopedic insert under my right heel.
The FAA regs that I've seen posted on MSNBC and CNN say that umbrellas and canes are acceptable once they are examined.