- Uncredited Role: Nick Cravat is uncredited as the gremlin.
- Unintentional Period Piece:
- Well fancy that, someone with a gun on an airplane, in plain sight. Needless to say this episode wouldn't really work nowadays.
- When Bob takes out a cigarette, his wife tells him to put it away... The plane hasn't taken off yet, after all.
- What Could Have Been: Richard Matheson, who wrote both this and William Shatner's other episode, "Nick Of Time", sought his co-star Patricia Breslin to reappear as his wife in this one as well, but she was unavailable.
- Underage Casting: The thirty-seven-year-old Robert Wilson is played by 32-year-old William Shatner.
Trivia / The Twilight Zone S5 E123 "Nightmare at 20,000 Feet"