United States President Donald Trump attended the Ryder Cup to a chorus of cheers from his supporters at Bethpage Black, as the biennial golf mega-event kicked off on Long Island.

Trump flew over the course on Air Force One as the U.S team was off to a poor start on Friday against defending champions Team Europe, who raced out to a 3-1 lead in the morning foursomes on the first day of the match play competition.

He arrived on the grounds just as the duo of Xander Schauffele and Patrick Cantlay beat Europe's Robert MacIntyre and Viktor Hovland 2UP to avoid a U.S shutout in the first session of the day.

"I think we'll be okay," Trump told reporters on the tarmac. "All great golfers."

It was hardly the start the Americans had hoped for as they look to recapture the trophy on home soil after losing the 2023 edition.

"We just had the President fly over in his Air Force One, so I have a feeling things are going to turn around here," U.S team captain Keegan Bradley said.

Heightened security measures and bumper-to-bumper traffic greeted fans, many of whom had shelled out more than $1000 apiece ($A1500) for tickets and shuffled in long before the sun was up to catch sight of twice major winner Jon Rahm teeing off for Team Europe.

Unlike at the U.S Open men's tennis final earlier this month in Queens, where Trump's arrival caused security delays for fans, Ryder Cup ticketholders navigated the layers of security with relative ease.

Trump shook hands and pumped his fist as he stepped into the stands while fans chanted "USA! USA! USA!" before the U.S anthem played with a military plane flyover.

He was accompanied by his teenage granddaughter, Kai, who is a recreational golfer.

Wearing white golf shoes, Trump later walked on to the course to give American Bryson DeChambeau a fist bump as the twice major winner prepared to begin his fourball match with teammate Ben Griffin.

They ended up losing 1UP to Tommy Fleetwood and Justin Rose.

He departed before the quartet of afternoon fourball matches had reached the back nine.

It was a far warmer welcome than Trump received at the Super Bowl and at the U.S Open, as the U.S president has repeatedly sought to thrust himself into the spotlight at sporting events during his second term.

A persistent hum of helicopters overhead served as a reminder of the sky-high security measures in place at the notoriously rowdy biennial golf showcase, where organisers and local officials repeatedly urged fans to arrive early.

Trump is a huge proponent of LIV Golf, a rival body to the PGA, but which has been involved in on-going talks to unify the sport.