This isn't just a one-off is it. There are often reports of various members of the royal family commissioning trains, planes and ships for their sole use. I think some people, me included, feel that being so profligate, and disregarding the effect on the environment that they claim to cherish, doesn't reflect well on any of them.
Those who have no enthusiasm for the monarchy, with its implicit acceptance of the notion of inherited privilege and power, are in the minority. But it is a much larger, and growing minority than a few centuries ago when even those who suffered at the hands of their kings and queens - taxed to the hilt in order for their "betters" to be able to satisfy their every whim and to engage in stupid wars - would defend them to the death. Thankfully, we've moved on a bit from that but still people genuflect in their presence and treat them like some sort of deity. It's astonishing what a good PR machine and a supine media can achieve.