Fighter pilots

Free to read here, from Project Gutenberg.

The Red Battle Flyer

Manfred Richthofen, Freiherr von, also an audiobook

Der rote Kampfflieger

Manfred Richthofen, Freiherr von

German

High Adventure: A Narrative of Air Fighting in France

James Norman Hall, also an audiobook

Winged warfare

William Avery Bishop

The Brighton Boys with the Flying Corps

James R. Driscoll

A Yankee Flier in the Far East

Rutherford G. Montgomery

Punainen lentohävittäjä

Manfred Richthofen, Freiherr von

Finnish