Hello Aspirant,
BBA in aviation is 3 year programme which focuses on managerial skills. Eligiblity is 10+2 from recognized board. There are total six semesters and final year end up with doing internship that is of 6 months.
Best colleges:-
1. UPES
2. GD Goneka University
3. Osmania University
And many more
The course is best suited for those who want to build their career in management responsiblities. Fees is around 18,000-2.6 laks. Average salary:- 2-6 lakhs. Top recruiters are Aviation Industry, Airline/port, Airline Insurance, Contracting, sales operations.
On the other hand CS or company secretary it's a senior position in a private sector. CS it's typically named a corporate secratory. CS is responsible for the effiecient administration is a company.
There are 3 levels:-
1. Foundation programme
2. Executive programme
3. Professional programme
Eligiblity:- 12th from recognized board.
Fees is different for different levels.
If one wishes to pursue CS after graduation he/she will undergo only level 2 and level 3.
Average salary:- Rs 4 laks for freshers
You can also pursue CS while doing graduation.

Both courses are equally good. It depend on your interest which you want to opt for.

It solely depends on the filed in which you want to take your career to. You can BBA and CS if you want to take your career in law field. If you don't want to do law and want to do MBA after BBA, then CS is all of no use. With BBA in aviation, you can get profiles such as Credit Control Manager, Airport Manager, Test Manager, Program Manager, Assistant Airport Manager, Airport Operations Manager. It totally depends on you, where you want to see yourself in the upcoming years.