Columbia subject headings:
Harvard subject headings:
Aircraft industry--Germany--History--20th century.
Airplanes--Germany--Design and construction--History--20th century.
Airplanes--Germany--Maintenance and repair--History--20th century.
Princeton subject headings:
Aircraft industry--Germany--History--20th century.
Airplanes--Germany--Design and construction--History--20th century.
Airplanes--Germany--Maintenance and repair--History--20th century.