questions regarding promotion, fleet expansion, how much money you gonna give me and when
Those are the WORST kind of questions you could possibly ask. You must must must leave that interview with the employer feeling warm fuzzies about how much YOU can give THEM and not vice versa.
Remember above all that the only purpose of the interview is to secure the job offer - you have all the time in the world to get the questions you really want answered
once they've offered you the job.
Since the question time is probably the last part of the interview it's one of the most critical because it's your very last chance to create a good impression before you walk away and wait for the phone call. It's all about selling yourself right to the bitter end ...
"How long is the bond" is probably the worst possible opening gambit for a turboprop employer. In fact don't go down the road of pay / conditions / bonds / promotions etc at all.
Example of one that worked really well for me once was "If I get this job I'd like to buy a property in xxx town (half an hour's drive away), what is your time requirement for pilots on standby to report for duty, because I'm afraid it might be too far away?" Bingo, instantly made them think I really wanted the job and was in it for the long term because I'd already been looking to buy a house there.
Obviously it's got to be situation specific for the job but the trick is to load every question with something that's going to push their happy buttons. If you can't think of anything along those lines then it's better just to smile and say you've got no questions, than to ask awkward ones about what's in it for you.