Normally, CAD system is just a design/drawing tool, which will just help you to achieve your idea into 2D/3D drawings.
CAE system will not only achieve simeple functions of the CAD systems but also some simulations and Analysis to help you check, analyse and improve your design. Generally, A CAE system will help you to creat the virtural produciton and make some kinds of Analysis.
The CAE is the FUTURE.