I just read an interesting article, about carry-on items for aircraft travel.  Before December 30, if you wanted to bring your guitar or other larger musical instrument with you for airplane travel, most likely it would have to be checked.  This rule has changed. Now, according to the US Department of Transportation, if you get on the airplane and there is enough room in the overhead OR in a closet not being used (by crew member luggage or handicapped items) one may place their instrument in that space!  Guitar cases probably take up two spaces that luggage would fit, but no longer are you expected to take it out to make room for the bags.  I think the key to this is getting on first, or as early as you can so to make sure you will have room. And…just a tip: it might help to have a copy of this rule to show the agent working the flight who stands in front of the bag sizer.