The astrodome was a major innovation for celestial navigators. While earlier aircraft had observation hatches or even cupolas, the aerodynamic astrodome was well suited to the increasing speeds of aircraft and offered great visibility. Air Corps navigation engineer Thomas Thurlow began pushing for their development after his 1938 around-the-world flight with Howard Hughes. They did not last much past World War II as they were a weak point for pressurized aircraft and added significant drag as aircraft began moving closer to supersonic speeds.