Money: most projects didn’t have enough investment. Brin presumably can handle a conversation that starts with “We need another billion for…” Wind patterns are

Money: most projects didn’t have enough investment. Brin presumably can handle a conversation that starts with “We need another billion for…” Wind patterns are actually well understood: hot-hair ballons already move around simply by changing their altitude and going around reasonably freely. I don’t know if those could handle the jet stream, but that would make NY-London a lot faster. Agree with you on how slow previous prototypes have been: I was part of a project that tried to use them for urban transport, and it was not going nearly that fast… 65 knots is the speed of cars on a highway (at least the legal limit).