Now there is a good question. There is a third option of course - 'or is it reducing due to factors outside the control of anyone at the airport'. But first, let me add a few more thoughts....
I intended this question to be covered by my original statement, because, lets face it, the underlying assumption is that the airport themselves, know what the market is doing!
My gut feeling - and it is nothing more than gut - is that, in actual fact, the number of people crossing the bridge to fly out of Bristol to various destinations is not large enough to support the same services out of Cardiff. They are crossing the bridge precisely because Nice, Rome, Milan are destinations that will never "work" out of Cardiff.
The market here in Wales is reasonably well defined because the catchment area is reasonably well defined and almost impossible to increase. Its Eastern edge extends no further than the bridge and Chepstow, its Northern edge 10 miles North of the M4, its Western Edge Swansea, and Southern edge, well.....
Bristol on the other hand has a monstrous catchment area stretching all the way to Cornwall in one direction and half way to Gatwick and Birmingham in the other.
There just isn't the money in Wales during this intense period of economic uncertainty to generate large amounts of traffic out of Cardiff, especially when in addition to the tiny catchment area, the demand is for a limited range of Southern Spanish destinations at £9.99 a ticket.
Its the same reason there isn't a Cribbs Causeway or Cabot Circus in Cardiff. Instead, we have a Bridgend Outlet Mall.
Unfortunately I think 2011-2012 is going to be even tougher.