This study aims to investigate if we can use mixtures of biodiesel fuel (BDF) and diethyl ether (DEE) as substitutes for jet engine fuels. The BDF used here was actually derived from waste edible oils. The performance tests were conducted by using a micro gas turbine jet engine for a model plane. The fuels tested were JetA-1 and the BDE/DEE mixtures with DEE-concentrations from 0 to 25 wt%. The present test results show that the thermal efficiency tends to decrease with increasing DEE-concentrations up to 25 wt%, the BDE/DEE mixtures give almost the same thermal efficiency as JetA-1, but they give lower specific fuel consumptions than JetA-1 as a whole.