A friend of mine and I, we both interviewed a few months apart as regional FOs and they gave us the reason that we should upgrade and then reapply in 6 months. It beats me why they would want this when they regularly hire FOs from our regional and others. We noticed though that we were pretty young and had relatively clean records, while those who were hired tended to be of later age, 45 years and above.

It's probably only their way of testing to see whether we are really interested in Frontier or not. Then again, maybe we just suck at interviewing. Like I said, I went in mainly for the interview experience. A seasoned interview team will be readily able to spot the signs of an indifferent candidate.