A continuous in-line method for forming an airlaid fibrous fluff web adjacent the uppermost and lowermost surfaces of a substantially planar internal reinforcing ply having substantially the same width as said fibrous web, said ply being substantially impervious to the passage of fibers from one surface thereof to the other, in a continuous fiber deposition zone is disclosed. In a preferred embodiment, a unique ply folding board is employed to permit continuous formation of an airfelt web having a reinforcing ply comprised of wet strength tissue paper located approximately mid-way between its uppermost and lowermost surfaces. Two adjacent vacuum chambers are preferably employed in the continuous forming zone to compensate for the increased airflow restriction encountered when forming the uppermost fibrous web portion over the reinforcing ply and the lowermost fibrous web portion. In a particularly preferred embodiment, the position of the internal reinforcing ply relative to the uppermost and lowermost surfaces of the resultant airfelt web may be adjusted by advancing or retarding the position of the folding board within the fiber deposition zone.