The surprise announcement yesterday that NetJets Chairman David Sokol had resigned from Berkshire Hathaway under a cloud of insider trading suspicion produced smiles of satisfaction among many general aviation leaders. When the word of Sokol’s sudden exit spread during a dinner at the Sun ‘n Fun airshow in Lakeland, Fla., last night, one general aviation manufacturing CEO said, “There’s celebrating going on in Wichita and Savannah today.” Sokol cancelled orders for hundreds of business jets built by Cessna and Hawker Beechcraft, both based in Wichita, Kan., and Gulfstream, which is headquartered in Savannah, Ga. He said he did so to...