Trump recalled that the actions of the passengers and crew, which brought Flight 93 down in a Somerset County field, "just 20 minutes flying time" from Washington, D.C.
As the world remembers the thousands of people who lost their lives in the attack on the World Trade Center, President Trump flew to Johnstown, Pennsylvania with Melania this morning to attend a memorial event.
He paid tribute to victims at the new memorial as several services took place around the country to mark 17 years since the terror attacks. America will never ever submit to tyranny.
"Today all of America wraps up and joins together, we close our arms to help you shoulder your pain and to carry your great, great sorrow", Mr Trump said.
'We are here to pay solemn tribute to the passengers and crew members who rose up, defied the enemy...and changed the course of American history. It is believed that the hijackers were hoping to use the plane to attack the Capitol, home to the US House of Representatives and the Senate.
Cockpit voice recordings of the hijackers and mobile phone calls from those aboard to loved ones indicate passengers tried to fight their way into the cockpit to regain control before the plotters nosedived the plane. "America's future is written by our heroes", he said.
He said the site marks the "moment when America fought back", and said the september 11 anniversary recalls the day "a band of courageous patriots turned the tide on our nation's enemies and joined the immortal ranks of American heroes". "This is my holy place", his widow said before the ceremony began a moment of silence and tolling bells at 8:46 a.m., the time when the trade centre was hit by the first of two terrorist-piloted planes.
"17 years since September 11th!" he wrote in one tweet.
Trump noted that almost 7,000 service members have died since 9/11, and - using terminology avoided by his predecessors - said they were "facing down the menace of radical Islamic terrorism".
During the presidential campaign, Trump promised to keep the Guantánamo Bay prison open and to "load it up with some bad dudes", while in office, he has used the threat of terrorism to justify a travel ban, known as the Muslim ban.
"Even though I never met you", Isabella Del Corral said of her slain grandfather, Joseph Piskadlo, "I'll never forget you". Vice President Mike Pence represented the administration there on Tuesday.