Join Date: Feb 2015
Location: London
Programs: BAEC Silver, SPG Gold, Hilton Gold, Melia Gold, Shangri-La Jade, BA Amex PP, Iberia+, Nandos Card
Posts: 1,523
The "why have empty cabins" question has already been answered perfectly by nux and fitch upthread, not sure why people keep asking it.
It's also not a great comparison between long-haul flights with upgrades on domestic American flights or other carriers. Completely different drivers and interests both commercially and in terms of the product and perception they want their brand to project.