Bidspirit auction | Airmail. Letter sent by airmail

Airmail. Letter sent by airmail from Horta to Ponta Delgada via Lisbon. It bears the mark of the ”first transatlantic flight from Horta”, registered, postage of 1$75 from the Hélices series of airmail plus 1$10. Departed from Horta on 21/05/39, passed through Lisbon on 22/5 and from there continued to Ponta Delgada.