For example, a typical performance cruise power setting in a Cessna 172SP might be 70% rated power (180 BHP at sea level), which is way, way, way more than you'

For example, a typical performance cruise power setting in a Cessna 172SP might be 70% rated power (180 BHP at sea level), which is way, way, way more than you'd ever use for a sustained period in your car. Highway cruising might take 20-40 HP depending on your vehicle, which is probably more like 10% of rated power. 70% of rated power in a typical American car is probably like 120 MPH.