"Taxes & Charges" is the biggest con with LCC fares. Whilst the taxes may well be fixed (though they will vary from airport to airport), "charges" is a very grey area. Some of it will be airport security charges, but I suspect that also under "charges" comes additional (hidden) revenue. Personally, I find this sales technique crude. What the punter is really interested in is what the total comes to. So why not just advertise it as such?