A friend of mine was an Air Cdre and a thoroughly nice chap to boot. He saw the direction the RAF was taking, so decided to PVR...
He was holding some post in Washington at the time and entitled to fly Business / Upper Class or whatever across the pond. But the wretched bean counters told him he'd have to fly economy, because on the day of his flight he would cease to be in the RAF at midnight as his retirement took effect.
"Well, that's just confirmed to me that it's time to leave this sinking ship", he said. Fortunately the airline was made of better stuff and gave him a complimentary upgrade anyway.
Once upon a time, officers of Sqn Ldr and above were entitled to travel First Class on the choo-choo when on business, whether or not in uniform - RHIP as we used to say. But nowadays not even an Air Officer may travel in First Class, I gather...
The excellent Chiltern Railways has the right idea though. They don't have 'First Class' as such, but have a Business Zone on mainline trains which anyone can use for a small supplement of £10, although it costs slightly more (£25) on certain peak time trains. They make the point that you can upgrade to the Business Zone and get large tables for working, the widest seats with more legroom than you’ll find on any train service between Birmingham and London. So Business travel for those who actually need it, rather than a mere perk.