The rule of thumb from my senior aircraft design course was that 90% of the cost is designed in before you bend the first piece of sheet metal. Commercial prog

The rule of thumb from my senior aircraft design course was that 90% of the cost is designed in before you bend the first piece of sheet metal. Commercial programs have their own guidelines about how many planes you have to make to break even, and even there where they aren’t radically pushing the envelope it’s on the order of hundreds.