Hi Matthew,
Flights is a tricky one as its easy enough to get them setup but there is very little money to be made in affiliation with airlines. But I suppose every little helps!
If you have a look at AffiliateFuture.co.uk they have Virgin Atlantic there which you can affiliate with, you can also look at Opodo as they may be better for you due to their large variety of airlines and they also have other products such as hotels etc. But you could be looking as earning as little as 2.50GBP for a flight booking alone.
It also depends on what market of people are looking at your site - where they are travelling to as that could affect your affiliation.
Good luck
Chris
