What career prospects can an aeronautical student get in India?

This field is pretty new and under-developed as of now in India, primarily because of the huge investments it requires. The prominent government players, as rightly pointed out by Sanket, are ISRO, HAL, few DRDO labs like GTRE, ADA, DRDL and NAL. A few private companies like Tata, L & T, Mahindra, T