2 ms·

> But x2 fuel consumption is a hard lower bound. Can't you gain a bit of that back by flying higher than a subsonic design could?

• ddalex 7y ago
  Lift and drag are proportional. You fly higher you need to go faster as to get the same lift, and you'll encounter the same drag.
  • DuskStar 7y ago
    That's only true for induced drag, though. Parasitic drag is independent of lift, and would be reduced by flying higher.