Dear Harish,
Aeronautics deals with the study of aircraft material such as aeroplane, etc whereas aerospace deals with the concept of design, operation and construction of space vehicles.
Aerospace engineering is a skill based career and requires high expertise. You can go for public sector such as ISRO, ADE, NAL, DRDO and private sector such as Mahindra aerospace, Taneja aerospace. You can also work in abroad. The salary is very handsome.
In aerospace engineering is better from my point of view as it deals with space and aeronautical is a subdivision under aerospace engineering.
The choice is yours and both are good. Look out for your interest.
Regards
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