Different tracks feature different cars for you to drive. The most difficult to control are the aerial types. Learn to control those types during jumps as well on the tracks. Use the afterburner and air brake to control them during jumps and steer carefully when on the ground. Regular cars are easier to control and do not require use of the afterburner in mid-air for control. With ground-based cars, use the afterburner when the road is as straight as possible. Stop its use when a sharp turn is coming. With aerial cars, the afterburner is used to control the height and direction of the cars.