In the big picture though who is more likely / more capable to deliver the big passenger volumes long term - FlyBE or Ryanair? so it's a tough choice for an aiport managment.
Who would you say? Ryanair, predominantly serving leisure destinations, with a business model that requires payment of as little as possible in the way of airport fees - probably next to nothing at CWL; versus FlyBe, who, whilst they will also probably have a decent deal on fees from the airport, offer a mix of business and leisure related year round traffic.
Given that there is a market for business as well as leisure travel through CWL I would chose FlyBe over Ryanair every time. Not for passenger numbers, but for longer term sustainability.