In late March, Boeing announced that Calhoun would step down by the end of the year. The company also appointed Stephanie Pope as the new head of its commercial airplanes division, replacing Deal, amid falling stock value and increased regulatory scrutiny. Elon Musk Reacts: Tesla and SpaceX CEO Elon Musk, who is known for cryptic posts among other things, reacted to Calhoun's pay with an exclamation mark, possibly expressing surprise. Though most known as a commercial airplane maker, Boeing's other business unit also caters to making spacecraft, rivaling Musk's SpaceX.