The parents would have been deported as spies, and as a child of spies, Jeff would not be a citizen of the United States (according to the citizenship provision of the 14th amendment of the Constitution) and could also be deported.
Jeffrey says he need a new clutch for his truck, but in a scene before that he is driving and only makes one shift, after that the truck is heard making automatic transmission shifts and his arm does not move.
In an early scene, Parmenter and Grant meet in an office on Air Force Academy grounds. There is a State flag and a United States flag behind Parmenter's desk. The US flag is on the right, it should be on the left.
When Karpov gets into the cab after crossing the border, the camera, crew, lights and a bounce board are reflected in the window.
Karpov says to Grant when he first meets him: "Call me 'tovarishch', which means 'friend'." Tovarishch is the Russian word for comrade, while Droog is the word for friend.