You can't use parameters in the constructor.
I don't have an issue with what you are doing but I do have an issue with the way that you are naming object instances as though they are classes.
BookingCreator is an instance, not a class - it should be named 'bookingCreator'.
NEVER name variables with a capital letter at the start.
If you type 'MXML constructor' into Google you will get plenty of hits about this subject.
haha Its just an example mate... What you going to do come over and mark my work on use of caps? ... Im aware its an instance and it shouldnt start with cap... My appologies.
It's not an example, it's a bad example of a bad habit.
It's even worse that you post it knowing it's a bad example to others, since newbie developers will read that stuff and think it's OK.
I haven't time to mark all your usage of bad caps. Sorry.