[xenon]

I'm sure but it's all about numbers and efficiency. The A380 passenger costs / mile are fractional compared. These days high bypass turbofans are incredibly efficient but unsuited to faster-than-sound travel, for which you need an axial afterburning engine which is very thirsty and noisy. In terms of technology the fly-by-wire A380 and the new Boeing dreamliner are miles ahead of Concorde (obviously, given technical and computer progress) but they are obviously slower because of practicalities.

Given the ballache it is to fly these days with enhanced security check in times etc. etc. flying by private jet is the choice of the super rich.