Traveling on airplanes with musical instruments of any kind can be a challenge, Pianoforallparticularly if we're considering professionals who are carrying fine violins as opposed to a child traveling with an inexpensive student violin. But violins are not double basses, just as piccolos are not sousaphones. Size matters.
As does the particular carrier you are flying with, as well as the interpretation of the rules by each plane's flight crews. The rules on United Airlines might be different from those on Spirit, American, Southwest, Alaska and JetBlue airlines. Even the time you board your flight can make a difference.
But at least there are, since 2015, U.S. Federal Aviation Administration rules that bring a semblance of order and universal rules - and prevent last-minute price gouging that plagued musicians for a long time.
The following provides a quick run-down of the rules and recommendations for violinists, violists, cellists, double bassists, and, of course, musicians who play the viola da gamba: