Plot hole: All those years in the spy biz as U.N.C.L.E.'s very famous top agents, and Solo and Illya are still able to successfully go undercover with little or no disguise. Here, all Illya needs is a phony mustache and an even phonier accent. And of course (gotta love it), the Thrush bad guys still don't recognize him. (00:49:00)
Continuity mistake: The KGB's blue car is in good cosmetic condition when the car chase begins. But in one shot, as it's pursuing Solo, there's considerable damage to its front end - from a crash that doesn't happen until several shots later. (00:23:00)
Nigel Pennington-Smythe: You must be an old hand at this.
Napoleon Solo: Actually, I'm new at this... again.
Trivia: Although he's never addressed by name, it's heavily implied, and quite obvious, that George Lazenby's character is supposed to be James Bond.