@Manisha: Let me ask you a basic question. Do you feel more comfortable going and getting a TR on your own without any guarantee of a job? or with a LOI which, even though not a guarantee, is at least an official paper which states the company's intent to hire you?
To me the answer is very obvious.
According to me IndiGo requires a lot of FOs especially with the number of aircrafts they are getting. Just my 2 cents on the matter