This work is devoted to development of an alternative blended aviation fuel containing rapeseed- oil-based biocomponents and to a study of their physicochemical properties. The basic characteristics of a petroleum aviation fuel and three types of biocomponents are studied and analyzed for conformance to standard requirements of a Jet A-1-grade aviation fuel. It is shown that modification of air-jet engine (AJE) fuels with rapeseed oil esters enhances the density and viscosity of the fuel, raises the pour point, and broadens the fractional composition by virtue of elevation of the end-of-boiling temperatures, which is explained by increased energy of interaction between the molecules of the hydrocarbon fuel and the fatty acid esters. It is demonstrated that AJE fuels modified with up to 30 vol. % biocomponents meet the requirements of normative documents on the studied properties and can be used as a source of AJE energy.