Shares of AAR Corp. AIR, -3.53% were down 2.7% in afternoon trading, but pared earlier losses of as much as 8.3%, after the provider of aviation services said it had no part in the incident on the Alaska Air Group Inc.’s ALK, -0.65% flight that led to the grounding of some Boeing Co.’s BA, -7.02% 737 Max 9 planes. Still, the stock was headed for its eighth-straight loss, which would be the longest such streak since the eight-session stretch that ended June 16, 2016. “AAR did not perform any work on or near ...