A startup called Whisper Aero, which is disclosing its plans for the first time, thinks it may be well on its way to solving a noise problem related to drones.

On the evening of Nov. 16, Elon Musk unveiled the latest prop in his Tony Stark cosplay. Tesla Inc.’s all-electric semi rig met all the classic Musk product launch criteria: It looked stunning, had unprecedented performance numbers, included features straight out of science fiction, and would arrive at some unknown date at a too-good-to-be-true price from a still-to-be-built assembly line.