Hai Abishek the eligibility to becaome an aeronautical engineer is that one should have a graduate degree (B.E/B.Tech.) or at least a diploma in Aeronautics. The eligibility criteria for a BE / B.Tech is 10+2 or equivalent examination, with Physics, Chemistry and Mathematics with higher marks +entrance exams. So now what you should do is that ,study 10+2 or equivalent examination, with Physics, Chemistry and Mathematics and score higher marks and after that you can take BE / B.Tech or Dipoma. For details of aeronautical engineeringclick here