Well, if you're a space-loving, globe-hopping Emir who lives in Abu Dhabi but likes to do his weekly shop at Harrods, then don't worry, Etihad Airways has your back. Their new A380 has this cabin called The Residence, and it's essentially a swanky apartment on a plane.
Forget sharing a cabin, even if it is with other wealthy Emirs shopping at Harrods. Who wants to have to sit with THEM? For a mere (a mere/emir, geddit?) $20,000 for an eight hour flight (for now, it's just the Abu Dhabi-London route), you can have a living room, bedroom, and a private bathroom with a shower, measuring a total of 125 square feet. The Residences also have a private butler, specially trained by Savoy Hotels. IN THE SKY.
You can't upgrade, use reward miles or blackmail the cabin crew. The only way to get into this space is to pay cold, hard currency. Hello, incomprehensibly wealthy sheiks and Kanye West. If you care to see what it looks like and never fly again out of crippling envy and status anxiety, then feel free to peruse the gallery (butler - artist's impression):