He’s famous for leading the Doolittle Raid, but a lot of people aren’t aware of his contributions to aviation.

It’s impossible to fly in the clouds with your vestibular senses alone. Without looking at the ground, you can become disoriented and put the plane into a dangerous position and crash. Doolittle realized that to really achieve full freedom of flight a method of safely flying in the clouds was needed. He developed the artificial horizon and directional gyroscope, still used by pilots today. In 1929, he was the first person to take off, fly, and land a plane using only instruments, without view from outside the cockpit.

This is one of the most underrated things that helped make air travel possible. So next time your flight takes off on an rainy, overcast day, you can thank Jimmy Doolittle.