This study is based on the application requirements of fully polarimetric radar for aircraft detection and target recognition. We focus on fully polarimetric scattering characteristics of air targets, particularly the cross-polarimetric scattering mechanism and its availability. In the ultra-high frequency band, we conduct numerical modeling and simulation of stealth and non-stealth aircraft targets. The spatial distribution characteristics of polarimetric scattering for different aircraft targets are studied and compared, and the structures that could cause strong cross polarization are analyzed. The results of this study suggest that nonstealth aircraft have more polarimetric characteristics; this will help people use polarimetric radar for detecting aircraft.