Despite extensive efforts to keep demonstrators as far as possible from Mr Trump, footage appeared to show the billionaire being ushered inside on Friday evening as the pilot entered a no-fly zone.
The protester buzzed loudly past a group of onlookers at Turnberry’s five-star hotel as Mr Trump spoke with guests, trailing a banner that read: “Trump well below par.”
A reporter at the hotel tweeted to say the pilot had circled the resort, and that the president was taken indoors as a result.
Environmental campaign group Greenpeace shared a video of the incident, captioning it: “Watch as @realDonaldTrump tries to hide from our message flying right over his head.”
Images showed marksmen pointing their rifles at the powered parachute, which flew past at about 10pm.
Mark Williams, assistant chief constable of Police Scotland, said: “We are aware a powered parachute was flown in close proximity of the Turnberry Hotel earlier this evening.
“It is a criminal offence to fly within the airspace restriction zone and officers are carrying out enquiries to trace the pilot.
“Anyone with information regarding the incident is asked to contact Police Scotland via 101.”
Mr Trump arrived in Scotland earlier on Friday evening for a “private visit”, shortly after tens of thousands of demonstrators took to the streets across the UK to protest his visit.
Thousands of Scots gathered in Glasgow’s George Square, waving signs with messages such as “Give the weans Irn Bru not iron cages”.
Another protester told the tycoon-turned-politician: “Bolt ya rocket and make Scotland great again.”
Touching down at Glasgow Prestwick Airport at 8.22pm on Friday, Mr Trump and first lady Melania were watched by hundreds of people who had gathered at a viewing area close by.
The Trumps disembarked from Air Force One and were greeted, briefly, by Scottish Secretary David Mundell.
The paraglider protest capped a tumultuous day for Mr Trump, who was forced to show a measure of contrition after a newspaper interview in which he criticised Theresa May‘s Brexit approach, saying it would scupper a trade deal with the US.
But he repeated, while standing next to Ms May in a press conference, that he believed her rival Boris Johnson would make a good prime minister.
And he committed a faux pas when meeting the Queen by failing to bow, and walking in front of her as they inspected troops arrayed to greet him.
Later, the White House Twitter account incorrectly said Mr Trump was “departing the UK” for his Turnberry estate.