Once the exclusive domain of luxury first class suites, sliding privacy doors are steadily pushing beyond the curtain into the business class cabin.
Admittedly, only a handful of international airlines have launched business class seats with doors.
That leaderboard includes Delta Airlines, which debuted the business class door for its Delta One suites in mid-2016; Qatar Airways, with its elegant Qsuite in 2017; China Eastern, across its new Airbus A350 and Boeing 787 fleet; and British Airways' long-awaited Club Suite of 2019.
Yet the concept has had outsize impact across the industry.
"Will it have a door?" has become perhaps the number one question asked of all airlines contemplating their own next-generation business class – including the forthcoming Boeing 777-9 products of Cathay Pacific and Singapore Airlines.
The companies which create, design and manufacture seats for airlines – among them Adient, Collins, Jamco, Recaro, Stelia, Thompson – now include at least one business class platform with optional doors in their catalogues: bait for carriers looking to not just catch up to but leap ahead of their competitors.
But now that many high flyers have sampled those business suites of Qatar and co, is a door really a deal-breaker?
They have obvious benefits when snatching some sleep on long international flights. Blocking out the distractions of noise and aisle movement helps transform your seat into a cosy snooze-inducing cocoon.
A closed door can also be a boon for those who need to work above the clouds: given enough personal space and fast inflight WiFi, a private business class seat becomes an office above the clouds.
However, many travellers tell us that the 'novelty' of a door quickly disappears and after a few flights, they find themselves generally keeping the door open for most of the trip.
So this week, we're asking Executive Traveller readers who've flown in first or business class suites with doors: what's your preference? When do you keep the doors open, when do you close them, and does a door make that much of a difference to the overall experience? Share your thoughts in the comments area below.