I would think they are aiming at business-people in the first place indeed.But when you book well in advance you can make use of the promo tariff,which must also be appealing to leisure passengers. e.g. in september a return ticket(promo) SOU-Antwerp currently stands at about GBP102,which is less or similar than a return ticket from SOU to Jersey or let's say Limoges in the same period with Flybe. So VLM can be affordable aswell if you plan in advance. I guess their yield management is similar to that of other airlines these days. The closer you come to the departure date,the more you are likely to pay.