Patent ID: 8308106

Claim:
An aircraft, comprising: a hydrogen source; an oxygen source; a control system configured to actively control and vary the pressures at which the hydrogen and oxygen are supplied for reaction in the fuel cell, wherein the control system is configured to actively control and vary the reaction pressures of the fuel cell based on the altitude of the aircraft; one or more aircraft engines configured to provide all necessary thrust for the aircraft to fly; and a fuel cell configured to react hydrogen from the hydrogen source with oxygen from the oxygen source to generate power, wherein the fuel cell is configured to react the hydrogen with the oxygen, the hydrogen and oxygen each being supplied at a reaction pressure of less than one atmosphere absolute; wherein power generated by the fuel cell powers the one or more aircraft engines; and wherein the fuel cell is further configured to provide sufficient power for the one or more aircraft engines to enable the aircraft to loiter at altitude with the hydrogen and the oxygen being supplied for reaction in the fuel cell at reaction pressures of less than one atmosphere absolute.