Flight of the Nighthawks has a good narrative that flows rather nicely. However, the plotline is one of Feist's weaker works, resulting in a somewhat meandering and, in the end, cliched style.
The book begins focusing on the two boys, Tad and Zane, though somewhere along the line, Feist seemed to forget about them, leaving me wondering why he introduced them in the first place. Identifying a main character toward the end seemed rather difficult as it seemed to be spread out over numerous characters. While incorporating a number of different main characters into a storyline is not a poor writing technique, it fails here primarily because Feist seemed to have the two boys in mind, then changed his mind or became too involved with other ideas to continue with them. Therefore, they simply don't hold the book together.
The thrust of the series also seems to have devolved into a simple chasing after Leso Varen, an all-too-familiar plot of one evil wizard threatening the world and a race to stop him. While the threat of the talnoy and Dasati remain, they are relegated to the background. Even the return of the nighthawks, the very threat for which the book is titled, are not particularly threatening and seem only a rung on the ladder toward Leso Varen. For that matter, when dealing with the nighthawks, unlike in A Darkness at Sethanon, there was no real sense of danger. I felt little apprehension at the characters' activities when chasing after a guild of assassins, a deadness that seemed inappropriate.
Finally, the concluding chapters were simply cliche. While Feist took pains to never directly mention what the characters had come to conclude about Varen's hiding place, it was rather obvious and particularly unoriginal. For the author to drop mention of Kaspar and Tal and others' knowledge while not disclosing it to the reader, as if it were to be a great surprise and leaving the reader on the edge of his seat, was simply trite at the reveal. Both more subtlety and creativity was warranted.
Still, I didn't find myself bored with the book until the last few chapters, and most of my frustrations really came about after reflecting on the storyline. Feist's writing style is generally fluid and interesting, which makes this book a reasonably enjoyable read, just not one that anybody should expect much out of in the end.