Abstract: Diesel engines are proposed as the drive unit for aircrafts that operate reliably and trouble-free even at great altitudes, wherein the combustion in the diesel engines at top dead center is moved up to an earlier point in time according to the flight altitude and the corresponding barometric pressure. In addition, the charge pressure may be set to a constant value, which is not dependent on the flight altitude, and furthermore, the quantity of fuel supplied may be adjusted to a minimum fuel quantity adjusted to the respective charge pressure.