Not Just Cardiff Suffering
Guys, don't be too hard on yourselves. It's not so much Cardiff in particular but a lot of the UK is going through this. Just look at what has happened at Durham, Doncaster, Blackpool, Bournemouth, Prestwick. UK domestic travel is falling too which is really harming the regions.
I would say one of biggest contributors is APD which keeps on rising relentlessly. Airlines can't make the thinner margins possible at regional airports worthwhile in comparison to the bigger cities and mainland european opportunities. It means british people are flying less but that wealthier foreigners are flying in from abroad to London and other select key gateways. Until the government actually realizes the airline industry is not evil (by reducing APD, encouraging regional airline travel) we will see a real difficulty in recovering from this fall off in demand.