yes, there will be some friction, but it is negligible amount in front of the pressure region created.
there is a boundary layer formation on a solid surface moving in the fluid medium.
flow close to the surface is laminar,fluid (air) forms a skin on the surface of the wing,which reduces friction.
as far as i know friction should be interlocking of microscopic hills and valleys on two surfaces in contact.
boundary-layer separation occurs at supersonic speed,now if it's due to friction then i have no idea if it's due to friction.
What about super sonic and hypersonic speeds wouldnt friction play a major role