I’m curious about the assertion that speed is theoretically unnecessary. I’ve wondered about that myself in the past.
With enough wing area (and low enough weight per unit area) you can maintain flight with arbitrarily low airspeed. This is the approach taken by gliders with enormous wingspans for their weight. For aerodynamic lift you do need the product area x speed^2 to be sufficient though, so there’s a limit to how slow a compact object of given mass can go.
Hovering helicopters and VTOL jets take the approach of more directly moving air downward very fast instead of moving fast horizontally through the air and leaving downward-moving air in their wake.
With enough wing area (and low enough weight per unit area) you can maintain flight with arbitrarily low airspeed. This is the approach taken by gliders with enormous wingspans for their weight. For aerodynamic lift you do need the product area x speed^2 to be sufficient though, so there’s a limit to how slow a compact object of given mass can go.
Hovering helicopters and VTOL jets take the approach of more directly moving air downward very fast instead of moving fast horizontally through the air and leaving downward-moving air in their wake.