Flybe do not want to make any commitment to you until they are sure you are of a reasonable standard, character and they have a job available for you, much like any business in any sector these days. It sucks, but thats the way it is. No company wants to go back to the days when they couldn't get rid of anyone who isn't needed/unfit for the job because of the severe retribution threatened by unions.
IMHO, this is why I suggest avoiding integrated schemes outside of fully or part sponsored schemes!