Modem flame aerosol synthesis of nanoparticles is a rapidly changing terrain: While producing mainly simple oxide commodities such as silica or titania in the last few decades, a deeper understanding of the process allows now the production of more sophisticated products with high functionality. Advances in process simulation and diagnostics of early particle formation and growth contributed to this development. This is illustrated in the synthesis of heterogeneous catalysts, where dry flame technology can be used to produce highly active nanoparticles. That way, inorganic submicron particles with closely controlled morphology and composition are produced, giving rise to a series of new products or processes that have been dominated by wet chemistry for years.