Question: What German social reformer's brother was a German pioneer of aviation who became known as the "flying man"?

Context paragraphs:
Beatrice Brigden: Beatrice Alice Brigden (1888-1977) was a Canadian social reformer, feminist and politician.  She was a radical for her time, advocating for birth control, the intellectual parity of men and women, and economic security among many other issues.  She began her career as a social reformer under the guidance of the Methodist church's Social Gospel but moved more radically to the left when it became apparent from her work with immigrants and laborers that the church was not supportive of social and economic reforms.  She was one of the early members of the Brandon Labor Church and was a founder of both the People’s Forum Speaker’s Bureau and the Labor Women’s Social and Economic Conference, the latter of which was merged into the Co-operative Commonwealth Federation (Manitoba Section).  Though she was one of the founders of the Co-operative Commonwealth Federation she was unsuccessful in several attempts to win a seat in the Manitoba legislature.  In addition to her many programs for women, Brigden also was one of the founders of the Indian-Métis Friendship Centres.

Otto Lilienthal: Otto Lilienthal (23 May 1848 – 10 August 1896) was a German pioneer of aviation who became known as the "flying man".  He was the first person to make well-documented, repeated, successful flights with unpowered airplanes.  Newspapers and magazines published photographs of Lilienthal gliding, favorably influencing public and scientific opinion about the possibility of flying machines becoming practical.  On 9 August 1896, his glider stalled and he was unable to regain control.  Falling from about 15 m (50 ft), he broke his neck and died the next day, 10 August 1896.

Alice Salomon: Alice Salomon (19 April 1872, in Berlin – 30 August 1948) was a German social reformer and pioneer of social work as an academic discipline.  Her role was so important to German social work that a postage stamp (pictured) was issued in her memory.  A university, a park and a square in Berlin are all named after her.

Morrill Wyman: Morrill Wyman (July 25, 1812 in Chelmsford, Massachusetts – January 30, 1903 in Cambridge, Massachusetts) was an American physician and social reformer.  Best known today for his work on hay fever, he was one of the most respected doctors of his time, a social reformer, Harvard overseer, hospital president, and author in his long lifetime.

Victor Aimé Huber: Victor Aimé Huber (10 March 1800 – 19 July 1869) was a German social reformer, travel writer and a literature historian.

Marie Juchacz: Marie Juchacz (née Marie Gohlke; born Landsberg an der Warthe, 15 March 1879; died Düsseldorf, 28 January 1956) was a German social reformer.

Theodor Lohmann: Theodor Christian Lohmann (October 18, 1831 – August 31, 1905) was a 19th-century German administrative lawyer, civil servant and social reformer, second in importance only to Otto von Bismarck in the formation of the German social insurance system.  He is considered one of the major forces advocating for legislation for occupational safety and health, as co-architect of Bismarck's social security and as a seminal figure in the relation of "Diakonie" and social politics.

Sir Syed Sani Syed Ali Shah Bukhari: Sir Syed Sani Syed Ali Shah Bukhari (Urdu: سید علی شاہ بُخاری‎ ) (born 30 November 1914 – 30 March 1979) commonly known as Ali Shah,Sir Syed Sani, Molvi Saeeb, Sir Syed Kashmir, Chirag-i-Beerwah, or Musleh-Millat, was a 20th-century Kashmiri Muslim pragmatist, Islamic modernist, philosopher, Islamic jurist, social activist and educator in the Budgam district of Indian administered Jammu and Kashmir.  He founded Mazhar Ul Haq High School Beerwah in 1934 and Anjuman Mazhar Ul Haq in 1951.  He also reconstructed and expanded the Grand Jamia Masjid Beerwah.  He was the khateeb (Orator), Imam and Mirwaiz of the Grand Jamia Masjid Beerwah whose foundation stone was laid by his elder brother, Syed Syeed Shah Bukhari, in 1928.  Syed Shah Bukhari was the Imam/Mirwaiz of historical Jamia Masjid, Srinagar after Mirwaiz Yousef Sahib until he left the Kashmir Valley.  He is known as an early pioneer who recognized the critical role of education in the empowerment of the poor and disenfranchised in the Muslim community.  In more than one way, Bukhari was a social reformer and a national builder of Jammu and Kashmir, particularly Allaqa Beerwah, which forms a major part of central and north Kashmir.  He commanded respect from Sikhs, Hindus and Muslims for his views and dedication to the cause of education.

Amalie Raiffeisen: Amalie Raiffeisen (2 August 1846 - 11 January 1897) was a German social reformer.

Gustav Lilienthal: Gustav Lilienthal (October 9, 1849 – February 1, 1933) was a German social reformer, a pioneer in building and construction technology (Prefabricated buildings), inventor of different Construction sets (e. g. Anchor Stone Blocks) and involved in the pioneering work of his brother, Otto Lilienthal in aviation.

Supporting paragraphs: Gustav Lilienthal Otto Lilienthal
Answer: Gustav Lilienthal