I'm not terribly familiar with the works of Raymond E. Feist, which made Flight of the Nighthawks something of a pain to read. I do have one of his other novels in my library (though I can't recall if I actually read it or not) and one of his stories was in Legends II, but I really don't know much of the backstory that would have made Nighthawks more enjoyable. As far as I can make out, about 90% of the characters are from previous books, and the plot revolves around incidents from the previous books. Since I'm not familiar with any of this, the book was awfully confusing in parts, which is very annoying in a book that's part one of a series.
If it wasn't for this, I'd give the book a high rating. The characters were interesting, and the plot was action-packed--both of which are things I love in a book. Feist's writing style is pretty good, and the pacing in excellent. It's probably a good book if you're a fan of his writing.
Since I haven't read his other books, I can't give it a good recommendation. If you've read his other books, go for it. If you haven't, you should probably read his other ones first. Since this is the beginning of a new series, it's annoying that it begins in the middle of a greater story. Because of this, I can only give Flight of the Nighthawks three yo-yos.