[TalonDJ]

Wouldn't it be easier to tool up and build new entire planes?

No, because as long as you are building a new plane you would update things for the times. Which requires a lot of design effort. Even just copying takes a lot of time because Fairchild is not going to just hand you the blueprints. The task of designing a whole new airframe and testing it, even if it is suppose to be the same, is almost as hard as doing it from scratch. It does not seem like it should be, but it is.

[PAR35]

The task of designing a whole new airframe and testing it, even if it is suppose to be the same, is almost as hard as doing it from scratch. It does not seem like it should be, but it is.

The Russians seem to be pretty good at it.