https://www.cnn.com/travel/article/chaise-longue-double-level-airplane-seat-returns/index.html
I don't like the idea. You lose the overhead bins and carry-on luggage space. I think there is only enough space for personal item under the seats. For the upper seats, there is no way to stretch out your legs, unless there is a foot cutout in the partition. But then you will be kicking the head rest of person below or maybe be caught in a leg hold trap if the bottom person does a reclining lurch.
And I see lawsuits written all over the design. People on the bottom are going to be hit in the head by falling laptops or other items by top passenger trying to climb in or out of their upper seats. Or they may get splashed by hot coffee or tea being passed over to the upper window(?) seat passenger. And I am guessing flight attendents will suffer more repetitive work related injuries having to shoulder press food trays to the upper level.
The coffin-like lower seats will have the upper person's butt just about a foot from your face. The following article says you probably won't be bothered by farts, "unless it is especially forceful". What about projectile vomiting or explosive diarrhea? And if fold up seats are a good idea for accessibility, there is no reason not to install them in the current sewting plan (other than the additional cost plus extra maintenance for moving parts).
https://ca.news.yahoo.com/why-shouldnt-worry-gassy-passengers-190531450.html