|1.Manfred von Richthofen||25 when killed|
|2.René Fonck||24 at end of war|
|3.Edward Mannock||30 when killed|
|4.Billy Bishop||24 at end of war|
|5.Ernst Udet||22 at end of war|
|6.Raymond Collishaw||24 at end of war|
|7.James McCudden||23 when killed|
|8.Andrew Beauchamp-Proctor||24 at end of war|
|9.Erich Loewenhardt||21 when killed|
|10.Donald MacLaren||25 at end of war|
|11.Georges Guynemer||22 when killed|
|12.William George Barker||24 at end of war|
|13.Josef Jacobs||24 at end of war|
|14.Werner Voss||20 when killed|
|15.Robert A. Little||23 when killed|
|16.George McElroy||25 when killed|
|17.Fritz Rumey||27 when killed|
|18.Albert Ball||20 when killed|
|19.Rudolph Berthold||27 at end of war|
|20.Bruno Loerzer||27 at end of war|
|21.Paul Bäumer||22 at end of war|
|22.Tom F. Hazell||26 at end of war|
|23.Charles Nungesser||26 at end of war|
|24.Georges Madon||26 at end of war|
|25.Oswald Boelcke||25 when killed|
Order as per Wikipedia. It was going to be the top 20 until I noticed I could get Nungesser and Boelcke on there too.
Edward Mannock was the oldest of this group, at 30. He was an exceptional pilot in a lot of ways, not least with the amount of effort he devoted to ensuring that the younger pilots under his command (who knew him simply as "Mick") were properly schooled in how to survive. His devotion to his comrades manifested as an intense hatred of German pilots, and his actions and beliefs were a stark contrast to the perception of the First Air War as chivalrous.
Albert Ball and Werner Voss are the youngest listed, both aged 20 when they were killed.
Voss was a close friend and rival of Manfred von Richthofen. His final dogfight became legendary, as he single-handedly held off a squadron of planes led by James McCudden, before finally being shot down. "His flying was wonderful," McCudden said of Voss, "his courage magnificent and in my opinion he is the bravest German airman whom it has been my privilege to see fight."
Ball was a loner who was valued highly for his propaganda value. He spent his time on the ground gardening by himself, and the letters he wrote home showed a young man struggling with the repressive nature of his role, and his growing unhappiness at killing so many pilots. He crashed while pursuing the Red Baron's brother, Lothar von Richthofen, although it's unclear who (if anyone) shot him down.