In regards to getting a rejection letter, you may not get one. I know when I interviewed with an airline, they told us that we would hear back from them in about a week or two. They never sent anything about not getting the job. Just know that if you're invited to training, you made it past the interviews. If you're not invited to training that same day, that's the end of your interview. Don't be discouraged though. I went on a few interview for different airlines and it wasn't until I interviewed with United, that I have become a flight attendant for them. 8 month anniversary was today! Get some practice out of these interviews even if you don't make it. Good luck!