As the 5-cent stamp circulated nationwide, local postmasters and citizens became confused about how it could be used. It was denominated at the domestic air mail rate, and it showed a plane, but did not include the words "Air Mail." Could it be used as airmail postage or not?
Third Assistant Postmaster General Robert Regar prepared a memo that addressed the issue. "They are valid for all purposes," he wrote; however, when used for air mail delivery, the stamp had to be used on an approved air mail envelope or with the words “Via Air Mail” written on the envelope.