It might be an optimum design for a glider, e.g., here is a design for India's Space Shuttle https://dynaimage.cdn.cnn.com/cnn/c_fill,g_auto,w_1200,h_675,ar_16:

It might be an optimum design for a glider, e.g., here is a design for India's Space Shuttle https://dynaimage.cdn.cnn.com/cnn/c_fill,g_auto,w_1200,h_675,ar_16:9/https%3A%2F%2Fcdn.cnn.com%2Fcnnnext%2Fdam%2Fassets%2F160523134043-india-space-shuttle-test-1.jpg https://dynaimage.cdn.cnn.com/cnn/c_fill,g_auto,w_1200,h_675...