The family had English, Scottish, American, Dutch and Huguenot ancestry, and the children were raised "with an abiding love of music.
[2] Her parents divorced and although Sintes began a degree course at Rhodes University she did not enjoy it and in 1948 moved to London to join her father.
[2] However, her interest in a career in the air continued and she joined British Overseas Airways Corporation as a stewardess, working on flights to Europe, the Middle East and South America.
[6] In 1953, Sintes was licensed as a private pilot and worked to build enough hours in the air to earn her assistant instructor rating at Denham.
[6] She later recalled that during her training for the role that "I was initially ostracised by most of them and pointed remarks were made when I entered the room" and that it was where she met the most direct hostility of her career.
In 1971, her unusual status as a "lady jet pilot" was featured in an episode of Nationwide, a BBC news and current affairs programme, which interviewed the passengers she was flying to Tenerife.
[12] In 1953, two days before Yvonne van den Hoek married Eric Pope, the couple were flying a Tiger Moth when the fuel gauge suddenly plummeted towards empty.
Flying to the west of London, the only possible site to set down was Windsor Great Park, where the problem turned out to be the aircraft's faulty fuel gauge.
[2] In 1966 when on holiday in Menorca with her sons, Yvonne Pope met Miguel Sintes, a former medical student whose training had been disrupted by the Spanish Civil War.