BRS also has a number of physical and operational disadvantages such as being positioned within the Green Belt, a small site, short runway, often poor weather across its 600 feet-plus AMSL elevation and difficult surface connectivity, most which don’t apply at CWL yet the airport has not yet managed to use any of these factors to significantly benefit itself.
Impact of these sort of effects are often exagerated - airlines will work around them if the pax demand is there.
As to a major ‘low-cost’ airline presence at CWL, Ryanair gave evidence to the Westminster Welsh Affairs Committee last year when the committee was enquiring into APD devolution to Wales. The airline said that APD was holding it back at CWL and if it was reduced or abolished Ryanair would put in more services there. I don’t know if this was simply part of Ryanair’s rhetoric in its longstanding campaign to have aviation taxes reduced or abolished across its network or whether it really was CWL-specific.
Purely cost related, not CWL specifc - Ryanair are interested in reducing their cost of operation, and would have said the same anywhere