At the beginning when they board the jet in Vienna, there is a large Uncle logo on the outside by the door. When the jet is shown taking off and in flight, the logo is missing.
When the motorcycle gang attacks the convertible with Kuryakin, Solo, and Sandy, Kuryakin is shown driving with Sandy in the passenger seat. In another shot Kuryakin is shown in the back seat and Sandy in the driver's seat.
There are two shots of 8 motorcycles chasing Solo and Illya. Napolean takes care of two, so there should now be 6 bikers in pursuit. When the car is finally overtaken, there are approximately a dozen bikes in the shot.
Illya on the conveyor belt is filled with problems. Some shots of the chunks of ice being broken are repeated. There are blocks of ice in front or behind Illya when there shouldn't be. And Solo arrives in the nick of time to rescue Kuryakin when Illya could have simply saved himself by rolling off the conveyor belt.
After Randolph and his group jump off the jet, the jet is shown with the door closed, which would have been impossible.
When the cockpit of the UNCLE jet is shown it is not that of the Hawker Siddeley HS.125 Series 3A jet aircraft, but rather that of a North American B-25J Mitchell twin piston radial engine aircraft.