Paperback: 416 pages
Publisher: Orbit; New Ed edition (3 April 2003)
It's the Great War. The Boche have attacked the Allies, and the Allied response has lead to trench warfare. But there's something different. The new flyers, who began a few years before, have been asked to form squadrons, and to set out as scouts, and so on. Of course, after a bit, they start to attack the other side's flyers, and then individual squadrons are combined into whole wings, and the initial chivalric ideals get left behind.
This novel, the first of a trilogy (also available as a single omnibus edition), follows the evolution of aerial combat from 1914 - 1918 fairly closely, from the point of view of an Allied Air Ace. However, it does have its own little quirks - the enemy are the Roche, not the Boche, flyers fly dragons rather than planes, women are allowed in combat, and as you've realised by now, this is fantasy, not historical. But given all that, it's still quite an interesting take, though it'll be interesting to see how the story diverges in volumes 2 and 3.
World War I Flying Corps, with Dragons.