The Corvette that falls from the sky is a mid '70's/early '80's body style and the car that the doppelgänger drives is a '68-'72.
Cameron states in his show that you have to travel 600,000 feet to reach space. The Kármán line is generally regarded as the edge of space at only 330,000 feet. The US armed forces defines the edge of space at 264,000 feet.