A Times investigation found that U.S. passenger planes come dangerously close to crashing into each other far more frequently than the public knows.Sydney Ember, an economics reporter for The Times, explains why an aviation system known for its safety is producing such a steady stream of close calls.Guest: Sydney Ember, an economics correspondent for The New York Times.Background reading: Airline close calls happen far more often than previously known.What you need to know about turbulence.For more information on today’s episode, visit nytimes.com/thedaily. Transcripts of each episode will be made available by the next workday.