I probably shouldn't be fussy, since books about First World War aviation aren't always that easy to find (unless you happen to be near Cambridge University Library, in which case a little digging unearths a reasonable number). However, this book wasn't all that great to be honest. There was a lot about the pilots, and it was, in effect, a conglomeration of stories about individual pilots. There was a lot said about how the observers and the gunners and the pilots of reconnaisance aircraft deserved more recognition, but not a lot about those individuals. Most of the people followed were fighter pilots, generally aces (and often the more famous, high-scoring aces).
The first few chapters were very good, with some interesting stories about the early days of the Royal Flying Corps. Tortoise races, anyone? (Fly in a wind speed higher than your aircraft's top speed. The person who gets blown backwards the furthest is the winner!). However, the balance of the book wasn't great. 1916 and 1917 got the lions share of the book, with only two short chapters on 1918, despite the fact that there was a lot of fighting in 1918 and it was most of the year before the armistice was signed. There was a definite bias towards the Western Front and the RFC, with a handful of German pilots, a few French and American, an even smaller handful of Italian pilots (and the pilots of the RFC who went to Italy), and pretty much nothing about the Eastern Front, or the Austrian side of the fighting in Italy. In fact, it could probably have been improved by explicitly focussing on just the Western Front, rather than giving the lives of two or three Italian pilots, with a focus primarily on one of them. There were a lot of comparisons to the Second World War, and I'm not convinced they really helped explain anything.
That said, some of the personal stories were interesting. The Red Baron was described as a rabid dog who should've been shot, and there was a big emphasis on the fact that the war in the air wasn't chivalrous, but was really rather nasty and that even if they were knights of the air, knights weren't very nice when they were in battle. Wasn't entirely convinced by the description of the Red Baron to be perfectly honest, but there you go. There were some very amusing tales of various things that went on in the air, and some more poignant ones.
On the whole, it was pretty mediocre. If it weren't for the fact that it's quite difficult to find books on this topic, I'd probably say don't bother. It doesn't say anything particularly special, and you can probably find the amusing stories in just about any account of WWI aviation--there were some rather bizarre occurrences. I also felt that it was overly critical of Trenchard and his tactics. If you have an interest in the topic, it's reasonable. If you're not desperately interested, don't bother.
(Just realised: I should probably tell you who the author is. It's the one by Richard Townsend Bickers, published 1988)