New Delhi, March 14 -- Over the years, a regular Chinese campaign of sending warplanes flying toward Taiwan - the self-governing island it claims as its territory - has raised alarm from Taipei to Washington.

Now, a sharp drop in the number of flights in the past two weeks has analysts scratching their heads about what China's military may be up to. And that mystery carries risks, former U.S. defense official Drew Thompson said.

"There are so many theories and the lack of understanding of China's intentions is what's disconcerting," said Thompson, now a senior fellow at the S. Rajaratnam School of International Studies in Singapore. "You fill the void with uncertainty, and uncertainty increases risk."

Flights stopped for 7 straight day...