The Federal Aviation Administration was hit with a class-action lawsuit last year alleging it had denied 1,000 would-be air traffic controllers jobs because of diversity hiring targets — as it was revealed that staffing levels were “not normal” at the time of this week’s deadly midair collision. Complaints about the FAA’s hiring policies resurfaced after the American Airlines passenger plane and a Black Hawk helicopter crashed in Washington, DC, on Wednesday, killing 67 people in the country’s deadliest aviation disaster in almost a quarter-century. Details of the litigation re-emerged, too, as Andrew Brigida, the lead plaintiff in the suit, suggested...