[1] The aircraft first flew in July 1939 but it failed to interest the United States Army Air Corps.

Howard Hughes' business partner, J.B. Alexander, backed the project and had flown in early examples of the aircraft.

[2] Harlow licensed the manufacturing rights to the PC-5 to Cub Aircraft of Canada during the wartime buildup.

Using an engineering team brought in by Intercontinental, a cheaper version of the PC-5 was developed and built as the PC-6.

The PC-6 wing failed, causing a fatal accident during an early test flight.