No you are offered a future contract of employment before training...i am sure there will be a get out clause for them but equally they are lending you 20 grand over a 4.5 year period so i can't see them not wanting you.
If they don't need anymore FO's come 2012 when the people on this course graduate i would imagine they will be put into the pool and will get first shout at any job openings.
Flybe have to get their investment back.