Studies on the atomization characteristics of sustainable aviation fuels (SAF) such as drop-in aviation biofuels from aircraft engine atomizers are essential to counter the rise in aviation-caused CO2 emissions in the atmosphere. The present study analyses the drop size characteristics of fuel sprays of camelina- and jatropha-derived drop-in aviation biofuels from a hybrid airblast atomizer (HAA) used in aircraft engines. To begin with salient details of hybrid atomization are studied through experiments using water at different liquid and air flow rates. The spray characterization work of four different drop-in aviation biofuels, derived through the blending of camelina/jatropha HRJ biofuels and Jet A-1, from the HAA is done subsequently. The fuel spray experiments are carried out at six test conditions. The mean drop size (Sauter mean diameter, SMD) variations of the HAA spray are compared with predictions obtained from correlations reported in the literature. Likewise, the SMD trends of the hybrid atomization are compared with that of the simplex swirl atomization. Using the current data of the HAA spray of six experimental fluids, a new correlation for non-dimensionalized SMD in terms of liquid and air Weber numbers and Ohnesorge number is proposed, which facilitates the determination of mean droplet size of futuristic alternative aviation fuel sprays from the hybrid airblast atomizers.