What’s to blame for a summer of flight disruptions. And the legacy of pioneering “Star Trek” actress Nichelle Nichols.Read more:This summer has been filled with air travel issues: canceled flights, lost baggage, long lines. There’s been a lot of finger-pointing from airlines, at weather issues and short-staffed air traffic controllers, but federal data suggests the airlines themselves are to blame for many of the disruptions. Transportation correspondent Lori Aratani explains why airlines are still struggling to handle the demand for travel, and how to plan ahead when traveling. Nichelle Nichols, the actress best known for her role as Lt. Uhura in “Star Trek,” died last weekend at 89. David Betancourt discusses the road she paved for Black women in entertainment and the impact she had on the entire science fiction genre.