Yes, guitars can be brought on an airplane as either carry-on luggage or checked baggage. The type of guitar and size may affect whether it can be brought on board as a carry-on or needs to be checked in. It is recommended to check with the airline beforehand to understand their specific guidelines and restrictions for carrying musical instruments on the plane. Additionally, a hard-shell case is usually recommended to protect the guitar during travel. Remember to also consider any additional fees that may be associated with bringing a guitar on the plane.