If you travel with musical gear, but haven't read the DOT's press release (linked above), I highly recommend you do—especially in light of what United Airlines is gearing up for in 2017:
According to Jeffrey Dastin of Reuters, holders of United's new Basic Economy class of tickets will not be permitted to use the overhead bins for their luggage.
With that in mind, let's again review a bit of the DOT's press release:
"The rule requires that each U.S. carrier subject to this regulation allow a passenger to carry into the cabin and stow a small musical instrument, such as a violin or a guitar, in a suitable baggage compartment, such as the overhead bin or a closet, or under the seats, in accordance with FAA safety regulations and the carrier’s FAA-approved carry-on baggage program."
This begs the question: Will United Airlines let Basic Economy ticket-holders store their instrument in the overhead bin, if the instrument doesn't fit underneath the seat in front of them (or there is no closet s space)?
It looks very likely that this will result in higher ticket prices for musicians traveling on United.
While we're waiting for an answer, check out Dastin's article on the subject: