This won't surprise those who buy their tickets intelligently, although I suspect such folks are not in the majority! I use "full-fare" and "no-frills" as and when appropriate and I've got few complaints about the service I've received from either type of company.
For the business traveller, a couple of other things affect my decision:
(a) It's not just the convenience of the destination airport, it's also the departure location. For me (and I'm not alone) in leafy S Bucks, getting to Stansted for 05:00 is a pain and a taxi costs £100 each way (cf £35 for LHR).
(b) I'm frequently prepared to pay extra ('cos I pass the cost on to my clients
) for flexibility. I can't always forecast the end of my working day, so on non-flexible tickets I've either got to book a late flight or risk having to rebook at the last minute - which not only loses the ticket already purchased, but (as the article points out) is likely to be much more expensive.
Final thought - does buying last minute
inevitably increase the cost. If you're lucky (or the airline is unlucky) enough to get a lightly loaded flight, I would have thought last-minute tickets would be quite cheap?
PS I can't find the AUC info online, but
The Times has an article based on it.