COOPERSTOWN — The Glimmerglass Festival on Friday will open a season of favorite operas sure to entertain as well as intrigue. “I wanted the season to reflect America's 250th anniversary [in a way] that is meant to connect to the world we live in,” said Rob Ainsley, the company's artistic and general director. “The theater is one of the few civilized places to discuss things in a respectful way.” The opening will feature Rodgers and Hammerstein's “Oklahoma,” which will get 10 performances.