Hypergolic fuel propulsion systems contain a fuel composition and an oxidizer composition. The fuel composition contains an azide compound that has at least one tertiary nitrogen and at least one azide functional group, as well as a catalyst that contains at least one transition metal compound. The fuel composition optionally further contains a hydrocarbon fuel. The oxidizer composition contains hydrogen peroxide. The transition metal catalyst is preferably selected from the group consisting of compounds of cobalt and manganese. The invention provides a method for propelling a vehicle by providing a fuel mixture that spontaneously ignites with the oxidizer composition in an engine to provide thrust.