He messaged me a couple years ago and it matches with this post's description: "While the first half of the email was about the idea, invariably, the 2nd half was about how much money it was going to make."

  Point-to-point supersonic organ delivery

  Dear Derek,

  I'm Bob Cringely, an ancient Silicon Valley pundit. I also run a little
  CubeSat air-launch startup. Competition from SpaceX forced us to cut costs
  so we figured how to make an old French business jet fly Mach 1.6 on the
  fuel to fly Mach 0.8. Now we want to apply this tech to organ delivery.
  100 VTOL supersonic drones could serve the whole US operating from helipad
  to helipad at 1000 mph. Not autonomous, they'll have pilots on the ground.
  It's a $2 billion business with 75 percent margins but only we know how.
  Please pass it on.