  Using entropy statistics we analyse scaling patterns in terms of changes in
the ratios among product characteristics of 143 designs in civil aircraft. Two
allegedly dominant designs, the piston propeller DC3 and the turbofan Boeing
707, are shown to have triggered a scaling trajectory at the level of the
respective firms. Along these trajectories different variables have been scaled
at different moments in time: this points to the versatility of a dominant
design which allows a firm to react to a variety of user needs. Scaling at the
level of the industry took off only after subsequently reengineered models were
introduced, like the piston propeller Douglas DC4 and the turbofan Boeing 767.
The two scaling trajectories in civil aircraft corresponding to the piston
propeller and the turbofan paradigm can be compared with a single, less
pronounced scaling trajectory in helicopter technology for which we have data
during the period 1940-1996. Management and policy implications can be
specified in terms of the phases of codification at the firm and the industry
level.
