An undertaker who became enraged when told he couldn't smoke on a cross-country flight faces up to 20 years in prison for his conviction on a federal charge of interfering with a flight crew. James Tabacca, 34, also faces a $250,000 fine when he is sentenced Nov. 14 by U.S. District Judge Wallace Tashima. Jurors ruled Tuesday that Tabacca so intimidated a stewardess that she could not perform her duties. However, jurors rejected the prosecution's contention that Tabacca had also assaulted the flight attendent. A prosecutor had told the jury that Tabacca of Universal City became outraged when flight attendant Pamela Martinez tried to stop him from lighting up aboard a Trans World Airlines flight from Boston to Los Angeles on Dec. 30. He had been seated in the no-smoking section at the last minute.