Abstract: An aircraft with a fuselage that accommodates a floor panel and a fuel storage system, wherein the fuel storage system comprises a tank system with at least one main tank 5a that is arranged underneath the floor panel; a cross ventilation system with a plurality of ventilation lines for venting the tank system, wherein the plurality of ventilation lines comprises at least one crossing ventilation line 11a that is routed from a first lateral side of the tank system to an opposite second lateral side of the tank system; and wherein the at least one crossing ventilation line is routed underneath or in the floor panel from the first lateral side of the tank system to the second lateral side of the tank system.