If you fly regularly, you will realize that a substantial portion of all luggage brought on a plane technically does not pass the size dimension requirements.

If you fly regularly, you will realize that a substantial portion of all luggage brought on a plane technically does not pass the size dimension requirements. However, overhead compartments can still handle these "oversized" bags, and the flight attendants do not care as long as your bag is not blatantly breaking the rules. So storing a guitar on a plane? No problem. A lot of the other luggage shouldn't even be there.