MUMBAI, April 2 -- The Sahar police on Wednesday registered a case against an unidentified person after a note reading "Danger" was found on a tissue paper inside an aircraft at the Chhatrapati Shivaji Maharaj International Airport. Police said the Ahmedabad-bound IndiGo flight from Mumbai, scheduled to depart at 1.30am, was delayed by over eight hours after the note was discovered in the aircraft's galley area.The aircraft was moved to an isolation bay. "We had alerted the Bomb Detection and Disposal Squad (BDDS), which searched the plane. However, nothing suspicious was found," said Manoj Chalke, senior police inspector of Sahar Police Station, adding that a case was subsequently registered against an unknown person. "We are trying to identify and trace the accused."htc...