The Supermobile does not just duplicate Superman's powers, it acts as a conduit for the Man of Steel's powers, allowing him to channel them through the vehicle itself. The Supermanium hull of the shields Superman from red solar radiation that would rob him of his powers, making it so that he remains at the height of his abilities as long as he is within the vehicle. When Amazo remarks that no engine on Earth could react as quickly and easily as the Supermobile's, Superman responds, "You're right about that, Amazo! But who said anything about an engine?", revealing that the vehicle is powered completely by Superman himself.
Besides invulnerability and flight, the Supermobile also channels Superman's other powers using the following devices:
Large mechanical arms mounted on either side of the cockpit area, allowing Superman to both punch and grasp.
A scope on the control panel which can be adjusted to work with each of Superman's vision-related powers: normal, telescopic, microscopic, x-ray, heat, and night vision.
Air jets that pop out from various points around the vehicle, allowing Superman to use his super breath if he blows into a face mask attached to the control panel.
A monitor and other communications and listening devices substitute for his super hearing.