This is an entirely new topic to me. I've never even considered what "jaunty" means.
Check it out. Apparently it means noble or gentlemanly. Which is just the adjectives I'd associate with the top hat. I guess it could cover just about anything except silly hats.
How does it apply to other accessories? What, for example, is a jaunty car? Google suggests it's a fancy horse carriage. This is one of the top hits for "jaunty pants":
Maybe "jaunty" is just a jaunty word for "cool".