Yes, you will be able to join second year of B.Tech/B.E after your diploma.

The following are a few colleges you may consider:

Punjab Engineering College, Chandigarh

Anna University, Chennai

Jawaharlal Nehru Technological University, Hyderabad

Sardar Vallabhbhai Patel Institute of Technology

Hindustan College of Engineering, Chennai

Punjab Engineering College, Chandigarh

hi,

yes, you are eligible for b.tech lateral entry admission  in aeronautical engineering. a diploma in mechanical candidate can apply btech course on following subjects,

mechanical engineering,

production engineering,

automobile engineering,

aerospace engineering,

aeronautical engineering.

iits and nits has no lateral entry admission. but most of the state government and private institute has lateral entry admission policy for diploma pass candidates.