There have beem rumours that by 2010 all or most airlines will make a necessity having a degree, but many people say that it's a load of non-sense. In my opinion, I think airlines are more interested in knowing how well you fly rather than how good your are at studies; it just, perhaps, makes recruiting a lot more easier.
After all, a degree will take up valuable time you could get to build up hours, but on the other hand it's useful to pay up for your training.