NOVELTY - The vehicle e.g. aircraft vehicle comprises a driving device (22) with a fuel cell system (24) and with an impeller, which is propelled by electrical energy from the fuel cell system and produces a drive jet, a flow gap for the drive jet, and a heat transfer device, which is arranged at the flow gap and which is coupled to the fuel cell system. The heat transfer mechanism comprises foamed metal core, which is thermally coupled to the flow gap. A fluid-tight cover is arranged between the foamed metal core and the flow gap. The foamed metal core is formed by means of open-porous metal foam.    USE - The invention deals a vehicle such as aircraft vehicle, land vehicle and water vehicle.    ADVANTAGE - The vehicle e.g. aircraft vehicle can be operated with high efficiency and has low weight.    DETAILED DESCRIPTION - The vehicle e.g. aircraft vehicle comprises a driving device (22) with a fuel cell system (24) and with an impeller, which is propelled by electrical energy from the fuel cell system and produces a drive jet, a flow gap for the drive jet, and a heat transfer device, which is arranged at the flow gap and which is coupled to the fuel cell system. The heat transfer mechanism comprises foamed metal core, which is thermally coupled to the flow gap. A fluid-tight cover is arranged between the foamed metal core and the flow gap. The foamed metal core is formed by means of open-porous metal foam, has cohesive pores and/or channels, is led into cooling medium for the fuel cell system, and surrounds the flow gap. The foamed metal core is thermally contacted with an outer cover. The foamed metal core passes partially to the outer cover of the vehicle. Supply paths and discharge paths for cooling medium are integrated in the foamed metal core. The cooling medium is cooled through the heat transfer device. The drive jet medium is heated by the heat transfer mechanism. A cooling medium cycle is intended for the fuel cell system. The flow gap flows into the outer area, is limited by a wall and has a cylindrical form. The heat transfer device is a part of the cooling medium cycle, is arranged at the wall and comprises cooling medium tubes, which surround the flow gap. The cooling medium tubes are led parallel to an axis of the flow gap into grinding area and has a shape of meander and coil. The coil axis lies coaxially to the axis of the flow gap. The cooling surfaces are intended in the flow gap, are thermally contacted with the foamed metal core, are fixed at the foamed metal core, consist of a radial extension, and are formed at plate-shaped cooling sections. In or at the flow gap a porous structure is arranged, which is thermally contacted with the heat transfer device. The porous structure is made of a foamed metal and is arranged at a wall of the flow gap. The cooling medium has a smaller density than water and a freezing point below -10degreesC. The impeller and the flow gap are arranged back-to back. A fuel tank for the supply of the fuel cell system with oxidizer and/or fuel is arranged between the impeller and a fuel cell device. The fuel tank and an oxidizer tank are arranged side by side and between the fuel cell device and the impeller. An INDEPENDENT CLAIM is included for a method for the operation of a vehicle.    DESCRIPTION OF DRAWING(S) - The drawing shows an aircraft vehicle.    Lug (14)    Body (16)    Driving device (22)    Fuel cell system (24)    Fuel cell blocks. (30)