The airline sector was another laggard Thursday after a profit warning from American Airlines ( AAL ) sent the entire sector tumbling more than 3%. The longest winning streak on Wall Street since November was threatened by soft Chinese inflation data and little measurable progress on a trade deal, pulling US stock futures into the red and rekindling a flight into safe havens like precious metals and government securities. Losses were also mitigated by an upcoming appearance by Fed Chairman Jerome Powell later this afternoon at the Economic Club of Washington DC.