On Virgin Atlantic's flights they have a class called "Upper Class." It is essentially business class with some first class perks (like airport lounge access). Anyway, they have these unique seats that let you lay literally flat[0]. It is the only time I've ever slept on a flight, even most business class don't go flat they just tip back.

So sign me on for bunk beds.

[0] https://c8.alamy.com/comp/E87ARA/upper-class-on-a-virgin-atl...