First off, Luis is Portugal, perhaps the reason that so many people automatically think of the US airlines first is that the US has the largest commercial aviation market in the word, and the world's three largest airlines are based here. It makes sense that if this ever happened, a US airline would be the one to do it. Of course, this will never happen, because Britain (among other countries), won't even agree to open skies. They'd certainly never let a US airline, or an airline from any other country, buy British Airways. Such a drastic thing as a single global airline would require way too much governmental cooperation (they'd all have to grant 5th and 6th freedom rights for this to work), and no government would realistically grant a monopoly to another country's airline. This is especially true for all of those airlines around the world that are still at least partially owned by the government.