Ending a three-year hiatus, AMC Entertainment, the nation’s second-largest exhib, has rejoined the National Assn. of Theater Owners.With Carmike Cinemas joining the trade org last year, NATO reps all of the country’s major circuits, comprising more than 29,000 screens in North America. When AMC dropped out in 2001, it had cited the need for flexibility in pursuing its agenda on issues such as digital projection. “AMC is looking forward to actively working with fellow exhibitors to advance issues common to the industry,” company topper Peter Brown said Tuesday. “With AMC’s participation in NATO, the exhibition industry has never stood more united,” said NATO prexy John Fithian.