That's a question Qantas is asking, ahead of its Project Sunrise plans for flights nearly that long from Australia's east coast to New York and London, possibly by 2021.
And they didn't ask just anyone; they've surveyed the passengers on the airline's current 17.5 hour flights to those destinations from Australia's west coast, as the airline gets ready to choose between ultra-long-range versions of either the Airbus A350 or Boeing 777X.
The top five requests were, according to The Australian newspaper:
1. "Sense of separation" experiences such as virtual reality relaxation zones, audio mindfulness experiences and broader inflight entertainment
2. Spaces to do stretching or gentle exercises
3. Dedicated exercise zones, including exercise bikes or rowers
4. Refresh stations, offering cold drinks and snacks