This group consisted of Donald and Melania Trump, along with past presidents and their spouses.
Trained to assist USA army veterans as part of the VetDogs programme, Sully was joined by several army veterans - some of who were in wheelchairs from injuries incurred during their time in action - and one of the late president's sons, Neil Bush.
Trump has said some rather negative things about the Clintons and the Obamas in the past. He is lying in state in the Capitol Rotunda and will be buried Thursday in Texas after a state funeral service Wednesday at Washington National Cathedral. Democrat Bill Clinton coasted to victory, ending Bush's presidency.
Former US president George W. Bush shared a light moment with former First Lady Michelle Obama at the funeral for his father George H.W. Bush on Wednesday, appearing to slip her a piece of candy before the service began. The others are Alan Simpson, the former senator and acerbic wit from Wyoming; Brian Mulroney, the former Canadian prime minister who also gave a eulogy for Ronald Reagan; and presidential historian Jon Meacham.
The CIA, too, honored Bush, the only spy chief to become president, as three agency directors past and present joined the public in the viewing.
Bill Clark CQ Roll Call
"I'm just here to pay my respects", said Jane Hernandez, a retired physician.
Trump, the day before, spent 20 minutes visiting Bush family members, who were staying at Blair House, across the street from the White House.
Mr Trump repeatedly criticised Mr Bush Jnr's policies, not least his Middle Eastern military intervention, and defeated Jeb Bush, his brother, in the 2016 race for the Republican presidential nomination, dubbing him "low-energy Jeb".
Some national parks may be closed or have limited services to visitors.
Bush died Friday at the age of 94, just months after his lifelong sweetheart, wife Barbara, died.
The late Mr Bush called Mr Trump a "blowhard". On Tuesday, Sully - who's named after pilot Sully Sullenberger - sat alongside Bush's casket as it lay in the U.S. Capitol Rotunda.