Columbia subject headings:
Harvard subject headings:
Airlines--Germany (East)
Airlines--Germany--Berlin--History--20th century.
Airports--Germany--Berlin--History--20th century.
Interflug (Airline)--History.
Transport planes--Germany--Berlin--History--20th century.
Princeton subject headings:
Airlines--Germany (East).
Airlines--Germany--Berlin--History--20th century.
Airports--Germany--Berlin--History--20th century.
Interflug (Airline)--History.
Transport planes--Germany--Berlin--History--20th century.