President of Singapore, Singapore Arms and Flag and National Anthem Rules 2003… (2003)
“ Flying of Flag on vehicles, vessels and aircraft 5.— (1) The Flag shall not be flown on any motor vehicle except a motor vehicle in which— (a) the President is travelling; or (b) any Minister is travelling on official business. (2) The Flag shall not be flown on any vessel or aircraft except— (a) a Government vessel or aircraft; or (b) such other vessel or aircraft as may be authorised under any written law to fly the Flag. Manner of display of Flag 6.— (1) Subject to international practice, the Flag shall take precedence over all other flags when displayed in Singapore. ”
