Flap is marginally significant as the only western ever directed by Britain's Sir Carol Reed. Anthony Quinn is top-billed as Flapping Eagle, a modern-day Native American stuck on a squalid reservation. Though liquored up most of the time, Flapping Eagle undergoes an eleventh-hour social awakening. Making certain that the media is notified, he hijacks a train and heads for Phoenix, demanding full restoration of rights for his people. Played uneasily for laughs, Flap tries to make up for its shortcomings with a 1970s-style tragic ending, but by that time most of the audience has given up. The working title for Flap was <I>Nobody Loves Flapping Eagle</I>, which was closer to the name of source material, Clair Huffaker's novel Nobody Loves a Drunken Indian.
~ Hal Erickson, All Movie Guide