An ejector nozzle tube, having along its length an essentially constant, essentially oval hollow cross-section, with a leading edge nozzle, having a rounded exterior cross-section, being arranged at a flow leading-edge area of the ejector nozzle tube. The leading edge nozzle includes a plurality of grooves issuing to the top and bottom sides of the ejector nozzle tube and connecting to an interior of the ejector nozzle tube formed by the hollow profile. An aircraft engine has an optimized oil heat exchanger with at least one oil cooler disposed in a trailing-edge area of an aerofoil-type structure, with at least one flow entrance area being provided to supply ambient air to the oil cooler disposed in a flow duct. The ejector nozzle tube can be arranged downstream of the oil cooler in the flow duct.