Delgado wrote in praise of Adolf Hitler, who he considered as a genius and an example of human possibilities in the fields of politics, diplomacy, social organization and military, in 1941.

[3] The Transportes Aéreos Portugueses was founded on 14 March 1945 by Delgado, then Director of the Civil Aeronautics Secretariat, with the purchase of the first aircraft that year, two DC-3 Dakota.

[5] According to the testimony of Marshal Costa Gomes, Humberto Delgado decided to run for president because he failed to be appointed director of the NATO Defense College.

Humberto Delgado missed the much-desired appointment due to animus between him and the British Admiral Sir Michael Maynard Denny, former Commander-in-Chief of the Home Fleet.

Interviewed on 10 May 1958, in the Chave d'Ouro café and asked what would be his attitude towards Salazar, Delgado replied with the immediately sensational: "Obviamente, demito-o!"

[9] Tomás' margin was inflated by massive ballot-box stuffing by the PIDE, leading to speculation that Delgado might have actually won had Salazar allowed an honest election.

As a result, Delgado was the only opposition presidential candidate in the history of the Second Republic (including its first incarnation as the Ditadura Nacional) to stay in the race until election day.

In other years when opposition candidates attempted to run, they were forced to withdraw before the polls opened when it became clear Salazar would not allow them to campaign unhindered.

Delgado was expelled from the Portuguese military, and took refuge in the Brazilian embassy before going into exile, spending much of it in Brazil and later in Algeria, as a guest of Ben Bella.

During the period of his exile in Brazil was supported by Maria Pia of Saxe-Coburg and Gotha Braganza, a claimant to the Portuguese Throne, who helped monetarily and even offered him one of their residences in Rome so that the General could return to Europe.

After being lured into an ambush by the regime's secret police (PIDE) near the Spanish border town of Olivenza, Delgado and his Brazilian secretary, Arajaryr Moreira de Campos, were murdered on 13 February 1965 while trying to clandestinely enter Portugal.

PIDE subsequently claimed that the original plan was an extraordinary rendition in which Delgado was to be kidnapped and brought back to Portugal for trial.

A fictional version of the assassination is described (with a "General Machedo" and his secretary "Paulo Abreu") in the crime novel A Small Death in Lisbon by Robert Wilson.