Dame Mary Bailey, Lady Bailey, DBE (1 December 1890 – 29 July 1960), née Westenra, was a British aviator.
The daughter of Derrick Warner William Westenra, 5th Baron Rossmore, of Rossmore Castle, County Monaghan and his wife, Mittie (née Naylor), Bailey was known as one of the finest aviatrices of her time, who "personally guided a plane from England to the nether tip of South Africa and back" (Time, 28 January 1930). In January 1930 she was appointed Dame Commander of the Order of the British Empire (DBE).
The daughter of aristocratic parents, Lady Mary Bailey spent most of her childhood in Ireland where she was home schooled until she ran away in 1906. Adventurous from a young age, she apparently bought a motorbike in her youth and was gaining a reputation for speeding in car by 1914. During the first world war, Mary volunteered as an aviation mechanic and served in Britain and France, associated with the Royal Flying Corps.
She was awarded a pilot's licence in early 1927 and quickly started a sporting career. She became the first woman to fly across the Irish Sea. On 5 July 1927 she set a world's height record of 17,283 ft (5268 m) in a light aircraft category, flying DH.60 Cirrus II Moth.
Between 9 March and 30 April 1928, she made an 8,000 mile solo flight from Croydon to Cape Town, flying de Havilland Cirrus Moth with an extra fuel tank, then she made 18,000 mile journey back between September 1928 and 16 January 1929. The return journey involved flying across the Congo, then along the southern edge of the Sahara and up the west coast of Africa, then across Spain and France back home again. It was the longest solo flight and longest flight accomplished by a woman that far.
In 1927 and 1928 she twice won the Harmon Trophy as the world's outstanding aviatrix. She also participated in two F.A.I International Tourist Plane Contests - Challenge International de Tourisme 1929, which she completed off the contest, and Challenge International de Tourisme 1930, in which she took 31st place for 60 participants, being one of only two women.
In 1931, she became a member of a group of female pioneers for science, the members of which shared her adventurous and determined spirit.
She gained the rank of Section Officer in the service of the Women's Auxiliary Air Force, during World War II.
She married Sir Abraham "Abe" Bailey on 5 September 1911, being his second wife, and they had five children:
- Mittie Mary Starr Bailey (born 1 August 1913 — died 10 April 1961)
- Sir Derrick Thomas Louis Bailey, 3rd Bt (born 15 August 1918 — died 19 June 2009)
- Ann Hester Zia Bailey (born 15 August 1918)
- James Richard Abe Bailey (born 23 October 1919 — died 29 February 2000)
- Noreen Helen Rosemary Bailey (born 27 July 1921)
Lady Mary Bailey was also able to use her talents for aviation to take aerial photographs of important archaeological sites. She was very likely the first woman to accomplish this during her work in February 1931 on Kharga Oasis project in Egypt. Working closely with Gertrude Caton-Thompson and Elinor Wight Gardner, Bailey was able to take aerial photographs which presented an expansive overview of the archaeological site within just two weeks. These photographs accomplished what would have taken far longer to do on foot. In addition, there also revealed future excavation sites. Indeed, Lady Mary Bailey's valuable contribution to the Kharga Oasis expedition was both innovative and impressive.