The Really Good: Ms. Clowers (the author) is clearly passionate about children, parents, and their combined safety and comfort when traveling. This book captures some key points she has gathered through her extensive experience traveling with a child along with information gathered through interviews with experts with over 450 years of experience including gate agents, flight attendants, and pilots. The result is a handful of points where any one of them, if you had not figured it out for yourself, could be worth many times the cost of this book. (I found the packing tips and suggestions for seat selection particularly useful.)
The Somewhat Annoying: There is a lot of self-promotion. The author's web site hundreds of times in this 150 page book. On several occasions it appears five times on a single page. The book could have been made a lot shorter by using a different layout, moving the links to a page on the author's site, and then referencing that site far fewer times. Perhaps as a result the book could have been made available for a bit less.
The Bottom Line: I gave this book a good rating because it provides useful information that will contribute the safety and comfort of my wife and daughter. If it were about anything else the rating would have been considerably worse.