It is suggested that you do not waste any money by enrolling in these institutions. They are only concerned with making money. Frankfinn though has tie-ups with different airlines and may get you to the interview process. But doing the course is not going to help you in the longer run. 

Each airline has its own way of grooming and safety rules. You will end up spending a lot of money, only to get disappointed if not selected.

Instead of spending time and money here, follow these points as they will help you in better ways:

• Give a lot of interviews with different companies. It doesn't matter if it's an airline or any other company. Just apply for the job and go for the interview. 
• You do not have to take the job if you are selected, but witnessing it will give you a better understanding of how to crack an interview.
• This will give you a lot of confidence with each round and each interview.

Therefore, after giving plenty of interviews in different companies you will be prepared for the right one. With your experience, you will be able to take a confident approach to each question.