C'est probablement aussi simple que cela, et cela vaut pour les pilotes, les médecins, les avocats, les usineurs ou que sais-je encore.
If you want to keep them in, you have to keep people happy and you have to pay them or give them some kind of incentive to stay that will be at least as good as what they would get elsewhere, or they won't stay. It's probably as simple as that, whether they're pilots, doctors, lawyers, metal fitters, or whatever.
