The situation that grounded the U.S. aircraft industry is an example of what the Columbia law professor Michael Heller, in his new book, “The Gridlock Economy,” calls the “anticommons.” We hear a lot about the “tragedy of the commons”: if a valuable asset (a grazing field, say) is held in common, each individual will try to exploit as much of it as possible. Villagers will send all their cows out to graze at the same time, and soon the field will be useless. When there’s no ownership, the pursuit of individual self-interest can make everyone worse off. But Heller shows that having too much ownership creates its own problems. If too many people own individual parts of a valuable asset, it’s easy to end up with gridlock, since any one person can simply veto the use of the asset.