Study on use of aviation fuels in the internal combustion engines in road vehicles has been conducted for a long time. After the JP-8 is accepted as a single fuel on land and in the air (single fuel concept) by the North Atlantic Treaty Organization (NATO), the majority of these studies have focused on JP-8. For this reason, there is hardly any study on using the Jet A1, which is structurally very similar to the JP-8, in the internal combustion engine. However, in obligatory cases such as in periods of war, using the Jet A1 in the same way as the JP-8 in internal combustion engines may be required. In cold climates especially, the Jet A1 may gain strategic importance due to its very low freezing point. In this study, both the effects of the diesel and Jet A1 blends on engine performance and exhaust emissions in both the single cylinder, and the direct injection diesel engine have been examined. As a result, it has been determined that use of Jet A1 reduces engine torque to 5.85% and increases the specific fuel consumption to 8.77%. In addition, while there is an increase in smoke and carbon monoxide (CO) emissions 82% and 71.9%, respectively, there is a decrease in nitrogen oxide (NOx) emissions by 29%. In conclusion, there is no positive effect in using the Jet A1 in the diesel engine except for the reduction of NOx emission and the decrease of the freezing point.