Hi Nagaraj,

First I would like to tell you that both are different entrance exams. There is no connection between them. As per the schedule given by CBSE for NEET and AIIMS, Delhi for AIIMS, the NEET examination is conducted on 6th May 2018. Whereas AIIMS entrance examination is conducted on 27th May 2018.

NEET is not compulsory for appearing in AIIMS. Since both are different entrance exam. 

Hope it's clear. All the best!!