The Boeing 307 Stratoliner is a historic commercial aircraft that first flew in 1938. It was the first commercial airplane to feature a pressurized cabin, allowing it to fly at higher altitudes for a smoother ride. The Stratoliner was designed for long-distance travel and could carry up to 33 passengers. Powered by four Pratt & Whitney R-1830 engines, the Stratoliner had a cruising speed of around 200 miles per hour. It was used primarily by airlines and the military during its operational years, with only a limited number produced, making it a rare and significant piece of aviation history.