At the end Capt. Greer gives the Thomas family a lift back in the Air Rescue helicopter. Pete and Linc, who had arrived with Greer in the helicopter are left behind and they drive away in a blue car. Where did the blue car come from?
When the car catches fire, it transforms from a 1970 model Lincoln to an different early 60s [presumidly a 1962 or 1963} model Lincoln, as evidenced from the suicide doors and the hood opening from the rear. After the fire has been extinguished, the car is still the different early 60s Lincoln.
In the beginning when the thieves are trying to steal the car there are tire burnout streaks clearly visible presumably from earlier takes of the same scene.
It would be impossible for Beryl Mayes to prep and paint a car that size and have it ready to go in just a few hours, especially when, as he stated, he's the only one working in the shop.
In several shots the the large bundle of dynamite attached to the bottom of the car is visible. In several other shots the dynamite is nowhere to be seen.