| Westbound | Eastbound | ||
| New York | Flights 1 and 2 leave New York. | San Francisco | Flights 3 and 4 leave San Francisco at 4:30 a.m. |
| Pennsylvania | Flight 1: Heavy icing causes pilot to make forced landing, damaging tailskid and axle. Cannot continue. | Elko | Flight 3 and 4 change planes. Flight 3: Pilot stalls plane after takeoff, crashes, dies. Mail transferred to standby aircraft; flight continues. |
| Chicago | Flight 2: Reaches Chicago despite bad weather. But with rain, snow, and fog to the west, flight cannot continue. | Rawlins | Flight 4: Makes emergency landing at Rawlins to fix oil leak, continues. |
| North Platte | Flight 4: Jack Knight takes over. Ignition problem delays departure until 10:44 p.m. | ||
| Omaha | Flights 3 and 4 reach Omaha. Only replacement pilot available who knows route to Chicago refuses to fly due to bad weather. Flight 3 ends. Flight 4: Knight volunteers to fly on, despite weather and having never flown the route. Departs at 1:59 a.m. | ||
| Iowa City | Flight 4: Sky "dark as hob," with high clouds obscuring moon. "Sense of isolation that's hard to describe." Descends beneath low clouds into rough air to keep sight of ground, then encounters snow flurries. Spots flares at airport and lands to refuel. | ||
| Chicago | Flight 4: Fighting lack of sleep, Knight reaches Chicago at 8:40 a.m. Another pilot takes over. | ||
| New York | Flight 4: Reaches New York at 4:50 p.m. "Great jubilation" in the Post Office. |