1. Royal Aircraft Factory Engine B.E.2c 100HP © SSPL / Getty Images
2. Replica B.E.2c © Stephen Slater
3. Maurice Farman MF.11 ‘Shorthorn’ © Topfoto
4. Fokker E-III © Hulton Archive / Getty Images
6. Adolphe Pégoud, LC-DIG-ggbain-14327, Library of Congress Prints and Photographs Division
7. Death of Adolphe Pégoud, www.earlyaeroplanes.com
10. French airman Captain George Guynemer (1894–1917) © TopFoto
11. Recruitment poster © The National Army Museum / Mary Evans Picture Library
12. Women’s Participation in War © TopFoto
13. A downed German aircraft near Verdun. France, 1916 © Photo12 / UIG / Getty Images
14. A dead British pilot lies on the ground next © General Photographic Agency / Getty Images
15. A falling German airman © Mary Evans Picture Library
17. Riesenflugzeug Siemens-Schuckert VIII 1918, Wikipedia
18. Rittmeister Manfred Albrecht Freiherr von Richtofen. Courtesy Ken Hemmerling Oblt.d.R Sheffer Collection; www.earlyaeroplanes.com
19. French built Nieuport 11, also known as ‘Bébé’ © Hulton Archive/Getty Images
21. Captain Billy Bishop, V.C., Wikipedia Library and Archives Canada, PA-001654
22. Royal Aircraft Factory FE2d gunner.jpg; Wikipedia
23. Ernst Udet (1896–1941) © Roger Viollet / Getty Images
24. SPAD XIII © National Museum of the US Air Force
25. Sopwith Triplane © Karl Drage
27. Rotary engine © SSPL / Getty Images
28. Sopwith Camel © National Museum of the US Air Force
29. Eberhart SE-5E © National Museum of the US Air Force
30. Fokker D.VII © National Museum of the US Air Force
31. A German aerial shot of a bombing raid © Mary Evans / Sueddeutsche Zeitung Photo