Mathias Rust, who spent 14 months in a Soviet jail for flying a small plane into Red Square, says the stunt was worth the price and only the beginning of his efforts to improve East-West relations.

But he said his 1987 flight across 500 miles of Soviet airspace was "not responsible" and he wouldn't do it again."It was worth my freedom, my liberty," Rust told The Associated Press aboard the Lufthansa flight that took him home to West Germany after his release on Wednesday.

After arriving in Frankfurt, Rust was flown by private jet to Hanover, Norddeutsche Rundfunk radio reported. His family lives farther north, outside Hamburg.

The slim, bespectacled Rust said he decided years ago to make a dramatic statement for peace.

"The motives were, as I've always said, to improve relations between our countries with this flight, with my existence, with the landing - and to further the cause of peace in general," he told the radio early today.

He told the AP that the flight had improved Soviet-West German ties and was "only the beginning" of his efforts.

"I will continue the work, but no crimes, only legal things," he said. He did not elaborate.

Rust spoke in English with occasional Russian and German. He turned away the Lufthansa crew's offers of drinks and delicacies, asking instead for mineral water and a snack.

Rust said he was aware when he flew from Helsinki to Moscow that Soviet forces might shoot down his plane.

"The possibility existed, of course," he stated matter-of-factly.

Asked why he thought the Soviets, after sentencing him to four years in prison, decided to free him early, he replied, "Humanity."

Rust said he spent most of his time at Moscow's Lefortovo Prison relaxing, polishing his English in conversation with a Soviet cellmate, repairing books and reading "a small library."