Hotel / Hospitality Management

To make a career in hotel management or airport management, you can either pursue BBA and MBA in aviation management or hotel management. The other options are B.Sc in hotel management. The best option would be to go for hotel management.

No, it is only done offline.

IHM admissions are on the basis of NCHMCT exam and not on the basis of 12th marks.

The eligibility depends on the type of course that you wish to pursue. Details of some courses are stated below:
Diploma after completing class 10th from a recognised board with a minimum of 40% marks.
Bachelor's Degree: Class 10+2 examination with at least 50% marks.
Post-graduation degree: Bachelor's degree from a recognised university with at least 45% marks.
Graduate and PG programs may also require you to appear for entrance exams such as NCHMCT, AIMA UGAT, and E-Chat.

Please see:https://www.shiksha.com/hospitality-travel/hotel-hospitality-management/articles/popular-hotel-management-entrance-exams-in-india-2017-blogId-6838

NCHMCT JEE Books for general knowledge and scientific aptitude section are:
Manorama Yearbook
Pratiyogita Darpan
Pearson India Yearbook
Lucent's GK
Competition Review Yearbook
Arihant General Knowledge
More, you can find here:
https://www.shiksha.com/hospitality-travel/hotel-hospitality-management/articles/books-to-read-for-nchmct-jee-2016-blogId-10467

After doing B.Sc in hotel management, you can go for Masters in hotel management, M.Sc in hotel management and catering, M.Sc in hospitality and hotel administration, MBA in hotel management or MBA in tourism.