there are numerous ways for creating such movement, the CarChallange demos using physics and the keys are modifying the physical properties force and torque of the car collider.
force: Qt.point(twoAxisController.yAxis*8000, 0) torque: twoAxisController.xAxis*2000
You could remove the torque and instead do something like this on the force:
force: Qt.point(twoAxisController.xAxis*6000, twoAxisController.yAxis*6000)
Now the car won’t rotate but only move in x and y direction.