How long have classic cars been around for?

A car can be a classic (AKA antique) after it has been around for at least 20 years. As of now, cars from 1991 and earlier are now considered antique (classic) cars. Although classic cars are usually the ones that were considered "icons" such as the Mustang Boss/Fastback/Mach I, Ford Thunderbird (1955), Corvette (60s), etc, etc.