Five-year-old Adrian took the family car, and was only caught when police in Utah state stopped him on the freeway.
A patrolman spotted the SUV weaving across lanes at 30mph (50km/h), and issued a traffic stop, duly obeyed by the driver.
He was shocked to discover the child behind the wheel, who said he was on his way to buy a Lamborghini.
The boy told police that he had left home after his mother refused to buy him the luxury vehicle - lower-priced models cost over $180,000 (£144,000) - which sparked an argument.