In response to your replies, i would like to add that maybe you have worked for many airlines before, or what ever, but it is all down to experience. For example those crew in the low cost sector probably fly up to three times more than those in the charter sector. I work for a low cost airline, and I work 6 days a week, with 4 sector days ( in the summer months can be up to 6 sectors a day). Very rarely are you not called on a standby. This is where the experience factor may come into the argument. I feel that age is not a concern neither the quick promotion, but they do have without a doubt the flying experience which is the most important. Also with the low costs, you work with minimum crew (3) so you really have to learn quickly on how to handle a situation on your own cause you have to deal with it. you can't pass it on to anyone else.
Please don't think you charter crew don't work hard, but in retrospect to the low cost crews, they work damn hard! Just a thought