There's actually a non trivial amount of air in low earth orbit. For example the ISS or Starlink satellites would experienced drag and reenter in only a few years without periodic thrusting. At Starlink launch dispense they are even lower and reenter in days.
True, but I'd consider a height at which an object with sufficient speed will happily do a few orbits before eventually succumbing to drag to be safely in the "not air" realm.
