Abstract: Cryogenic fuel compositions including a cryogenic fuel and paraxyelene and a dual fuel aircraft system for an aircraft having at least one turbine engine, including a first fuel system for providing a first fuel from a first fuel tank to the turbine engine and a second fuel system for providing a cryogenic fuel composition and having a second fuel tank storing LNG and fluidly coupled to the turbine engine, an additive tank storing additives and fluidly coupled to the turbine engine and a mixing device configured to create the cryogenic fuel composition.