Recent Boeing innovation has given birth to a new breed of plane engines that travel 25% faster, with 40% less fuel consumption. However, these engines have one fatal flaw; their composite material resonates perfectly with the timbre of a banjo, and sympathetic vibrations from a nearby banjo player have been shown to shatter a fully functional engine in just four minutes of bluegrass-style plucking. For this reason, airport customs officers insist that banjos must be de-stringed and checked before takeoff.