The Government of India Bureau of Immigration specifies that
Even for re-entry into the country, an Indian national is required to be in possession of a valid Indian passport or travel document issued by Govt. of India.
Identity documents required for Indian Citizen coming from Nepal by Air:
(i) Valid National Passport.
(ii) Photo Identity card issued by the Government of India/State Govt./UT Administration in India to their employees or Election ID card issued by the Election Commission of India.
(iii) Emergency Certificate issued by Embassy of India, Kathmandu.
(iv) Identity Certificate issued by Embassy of India, Kathmandu.
(v) Persons in the age of group of above 65 years and below 15 years would be exempted from the requirement of approved identity documents mentioned at SL. No. (i), (ii), (iii) and (iv). However, they must have some documents with photograph to confirm their age and identity such as PAN card, Driving license, CGHS card, Ration card etc.
(vi) Children between the age group of 15 to 18 years may be allowed to travel between India and Nepal on the strength of Identity certificate issued by the principal of the school in the prescribed performa.
(vii) In case of a family (family means husband, wife, minor children and parents) traveling together, the approved identification documents at SL. No. (i), (ii), (iii) and (iv) would not be insisted from all the family members if one of the adult members of the family has in possession of one of the prescribed identification documents at SL. No. (i), (ii), (iii) and (iv). However, the other family members must have some proof of their identity with photograph and their relationship as a family viz. CGHS card, Ration card, Driving license, ID card issued by school/college etc.
Note: - Aadhaar (UID) card is not an acceptable travel document for travel to Nepal/Bhutan.