Currency Exchange Rates.
Quite a lot of publicity about foreign holidays being cheaper because the pound is stronger against the Euro and some other currencies such as for Turkey, Australia and South Africa. That's more relevant for accommodation, restaurants, car hire etc. when away, rather than flights.
On the other hand, sterling has fallen about 10% against the US dollar from about 6 months ago when I bought some. However, the dropping of APD for children if reflected in air fares should at least help family holidays to the USA.
How much of the big fall in oil prices will filter through to passengers or whether airlines will keep most of the savings to improve profitability remains to be seen, and will also depend to what extent they hedged their fuel and at what price.
I wonder what the net impact of all these factors will have on growth at MAN in 2015, plus of course the 'confidence' aspect. Many of the signs for MAN are encouraging although I imagine capacity for the summer is now pretty well fixed. The ACL report for the start of the summer for movements and available seats should be interesting and a good indicator.