The results of simulation and experimental data presented here demonstrate that the competition between chain branching and chain termination is the key factor in hydrogen-air flame propagation, including the temperature regime of the process and the formation of concentration limits. Self-heating becomes significant in developed combustion. It enhances the chain avalanche and ensures the temperature necessary for layer-by-layer chain ignition. By varying the ratio between the chain branching and termination rates by means of an inhibitor makes it possible to control the flame propagation process.