An aircraft, comprising: at least one fuel cell including an anode and a cathode for creating electrical and thermal energy by an electrochemical reaction; a thermal control subsystem including a cooling loop operably coupled to an inlet of the fuel cell via a cooling inlet conduit and to an outlet of the fuel cell via a cooling outlet conduit and a heating loop operably coupled to the inlet of the fuel cell via a heating inlet conduit and to the outlet of the fuel cell via a heating outlet conduit , the cooling loop being separate from the heating loop , the heating loop including a heating loop heat exchanger connected to the heating outlet conduit and the heating inlet conduit, and the cooling loop including a cooling loop heat exchanger connected to the cooling outlet conduit and the cooling inlet conduit; and whereby a warming fluid circulates within the heating loop and a cooling fluid circulates in the cooling loop; at least one temperature sensor embedded in the fuel cell for measuring a first temperature of the at least one fuel cell ; and a control unit electrically coupled to the at least one temperature sensor , the control unit being configured for increasing the first temperature to a second temperature in response to the first temperature being less than or equal to a selected temperature threshold; wherein the control unit is configured to operate the fuel cell in a warming mode by increasing the first temperature: and wherein the second temperature is higher than the selected temperature threshold wherein the control unit is configured to increase the temperature while the aircraft is in flight, on ground, and during aircraft parking; wherein the cooling loop includes a cooling fluid accumulator disposed along the cooling inlet conduit between the cooling loop heat exchanger and the inlet of the fuel cell and a pump configured to circulate the cooling fluid, wherein the cooling fluid accumulator is disposed upstream of the pump. at least one fuel cell including an anode and a cathode for creating electrical and thermal energy by an electrochemical reaction; a thermal control subsystem including a cooling loop operably coupled to an inlet of the fuel cell via a cooling inlet conduit and to an outlet of the fuel cell via a cooling outlet conduit and a heating loop operably coupled to the inlet of the fuel cell via a heating inlet conduit and to the outlet of the fuel cell via a heating outlet conduit , the cooling loop being separate from the heating loop , the heating loop including a heating loop heat exchanger connected to the heating outlet conduit and the heating inlet conduit, and the cooling loop including a cooling loop heat exchanger connected to the cooling outlet conduit and the cooling inlet conduit; and whereby a warming fluid circulates within the heating loop and a cooling fluid circulates in the cooling loop; at least one temperature sensor embedded in the fuel cell for measuring a first temperature of the at least one fuel cell ; and a control unit electrically coupled to the at least one temperature sensor , the control unit being configured for increasing the first temperature to a second temperature in response to the first temperature being less than or equal to a selected temperature threshold; wherein the control unit is configured to operate the fuel cell in a warming mode by increasing the first temperature: and wherein the second temperature is higher than the selected temperature threshold wherein the control unit is configured to increase the temperature while the aircraft is in flight, on ground, and during aircraft parking; wherein the cooling loop includes a cooling fluid accumulator disposed along the cooling inlet conduit between the cooling loop heat exchanger and the inlet of the fuel cell and a pump configured to circulate the cooling fluid, wherein the cooling fluid accumulator is disposed upstream of the pump. <EOS>