Totally agree with Charcoal. But go to Mens Warehouse when they have the sale, Buy One Get One. Then get a Navy Suit. Cant go wrong with that.
I have 2 suits for interviews, 1 Charcoal, and 1 Charcoal with pinstripes. Both got me hired at different carriers. I don't think airlines are looking for people to fit in to their uniforms any more. They want to see someone professionally dressed. Hell, with the pinstripe suit I had a shirt that was very light shade of pink with a grey and pink plaid tie...Rocked it. I would say don't try to be too conservative or conventional, but don't try to stand out from the crowd. Find the median. And don't forget, anything Slim or Skinny will not work.
Good luck!
And there are plenty of reasons to use a suit after an interview. So might as well invest in one...That is my thought. Every once in a while I'll take the wife out, and we will both go Business Formal! It's always a good time!