Gil Brewer wrote some great stories in his day, but Flight To Darkness isn't one of them. It's decent enough, I suppose, for fans of this type of amnesia-noir, but comes off like a hackneyed cliche in the plot department. Brewer does serve up some nice bits of descriptive text/inner monologue here and there, but the dialogue isn't anything special, so it makes it kind of hard to connect to the characters through their conversations. To make matters worse, New Pulp Press did a poor job editing the book (as in, I don't think they edited it at all, just scanned it in and said, "who cares?" like so many reprint publishers). As a result, the book is riddled with typos and missing words, which makes for an annoying reading experience. It's also horribly overpriced for barely being 200 pages, so I'd buy it used if you buy it all.
If you want to read Gil Brewer's best stories, try: The Vengeful Virgin, A Devil for O'Shaugnessy/ The Three-way Split (note that only The Three-Way Split is any good in this double feature, and by good, I mean fantastic), The Red Scarf, and the long out-of-print, but spectacular A Killer is Loose.