Perhaps one other thing to consider is: Do flybe have a future as a company? Will they still be here in 5 years, 10 years? I suppose you could ask this question for BA too, but flybe have had a very difficult time recently and it is a question I would be seriously considering.
I also think your figure of earning £69,000 a year as a Q400 captain after only 3 years sounds very, very ambitious. Is time to command in Flybe really 3 years and is the Q400 skippers salary £69,000 or is that the salary for an Emb skipper?
BA every time for me for the following reasons.
1. Job security
2. Creates options for moving fleets or even moving companies if you want.
3. Job security