The MiG 21 and L 39 have a lot in common , both the real planes avionics , systems and DCS modules depth of simulation fidelity . Both are delightfully analog and alive . There ' s a lot to do in both of them . The big difference is in the performance and difficulty . L 39 is a nice plane for learning and enjoying flight . MiG 21 is a nice plane for putting what you learned into practice and getting stuff done in a more serious and intense way . MiG 21 is a high performance delta wing design . It ' s made for going fast and intercepting bombers . Lately I ' ve been flying the randomly generated Interesting Missions search it in the L 39 and been loving it . Failures are brilliantly modeled . And it ' s just plain pleasant to fly the L 39 C with the gunsight dismounted , in VR . I wish I had more time to spend with it .