The quick montage of Clark travelling through Europe by air shows briefly a Boeing 727 with Braniff International livery. Braniff International didn't start flying to Europe until 1978 with Dallas/Fort Worth and London-Heathrow route and didn't have any intra-European flights as Pan Am did.
A Volvo driven by Clark is 200 Series (denoted by the massive bumpers, black rectangular grille, dual-color front turn signal indicators and side lamps) wasn't introduced until 1974, two years later.
A silver Porsche with a rear whale spoiler and wider track is a 911 Turbo (930), which didn't go into the production for the 1975 model year, three years after the scene took place.