In order to start any route within the airline industry a route stability and useable population needs to be established and marketed . This process usually takes around a year to complete for any airline .
Admittidly the Cardiff-Brussels service is a little low on passengers and not sustainable for any airline but to establish the route for high fare paying business pax this is what the airline has to put up with ( without encouraging the rif raf ) like the 50p seats encouraged from that of the Loco's .
Good luck 6G , some good routes coming . Some good and effective marketing will also help with the main business routes .