A passenger being dragged screaming and bleeding from a plane, nosediving stock prices and an underwhelming initial apology by the CEO of United Airlines have added up to a PR nightmare and then some for the carrier whose slogan is “Fly the Friendly Skies.”

Tallying the costs of the blunder, however, is no easy task.

The Chicago-based airline’s stock lost $250 million in value Tuesday. As a bonus, United (NYSE: UAL) torpedoed its brand, cost itself untold current and future customers, and…