On September 4, 1922, Doolittle completed the first transcontinental crossing in a single day, from Pablo Beach to Rockwell Field, in 21 hours, 20 minutes, a distance of flying a DH-4 of the 90th Squadron. Mitchell concluded that accomplishing the same feat by "daylight only", making only a single stop at Kelly Field, had tremendous value, and staged a dawn-to-dusk transcontinental flight across the United States in the summer of 1924 in a Curtiss Curtiss PW-8 fighter developed from the R-6 for that purpose.