According to Mike Connors, he suffered two injuries during the filming of the pilot that continued to give him discomfort for the rest of his life. In the sequence on the golf course, during one of the shots when the helicopter plunged toward him, he threw himself to the ground and dislocated his right shoulder on a hill he hadn't realized was there. And in the fight sequence in the palm grove with Lloyd Nolan's henchman, he broke his left wrist when throwing a punch. Connors slipped in the muddy water and hit harder than he had intended, and his punch landed on a steel back brace that he had not known the other actor was wearing. In subsequent shots, Connors wore a soft cast on that wrist, and kept his left hand out of camera range.
When Dubrio's henchman abducts Mannix at the Palm Springs airport, the rental-car girl delivering his car asks if something is wrong, and Mannix replies, "No. He just tried harder." This is a reference to the long running Avis rental ad campaign "We try Harder", aimed at their main rival, Hertz.
John Colicos' character is supposed to drive Mannix to the airport control tower in the desert following the scene at the Palm Springs aerial tramway. According to Mike Connors in an interview that he and Joseph Campanella provided for the new DVD set, Colicos, who had theretofore lived in New York City, confessed that he had never driven a car. Connors covered for him by holding the steering wheel with one hand below the camera range and putting his left foot on the gas - which fitted into the sequence, when Mannix is supposed to hit the gas at the last minute as they approach the tower and race the car toward it.
The screen in the opening credits (on this and all subsequent episodes) that says "Mike Connors is" shows the colors of the Armenian flag - red, blue & orange, from top to bottom. Mike Connors of course is Armenian, and his real name is Krikor Ohanian.