But even before the National Transportation Safety Board completes its investigation—a neurotically thorough process that will probably take about a year, and thus meshes poorly with the news cycle and the conspiracy-theorist cycle—it is easy to see some of the lines of inquiry that crash detectives will pursue.

President Trump weighed in on the Wednesday evening crash between an American Airlines plane and military helicopter in Washington, claiming it “should have been prevented.” “The airplane was on a