George HW Bush has made his final trip to Washington aboard Air Force One as four days of mourning for the former US president begins.

Cannons fired in tribute at a Texas Air National Guard base outside Houston on Tuesday morning (Australian time), where the 41st president’s flag-draped casket was loaded on to the presidential jet.

Called “Special Air Mission 41”, the flight to Joint Base Andrews outside of Washington was joined by family and mourners.

Mr Bush’s son, former president George W Bush, and wife Laura Bush, were among relatives and friends who boarded the aircraft shortly after the body was loaded aboard.

The deceased Mr Bush will lie in state at the US Capitol Rotunda from Monday through Wednesday, when a state funeral is scheduled at the National Cathedral.

George W Bush accompanied his father to Washington. Photo: Office of George HW Bush

Mr Bush died at his Houston home on Friday night, seven months after his wife Barbara died.

After services in Washington, there will be another funeral in Houston on Thursday followed by burial at the Bush Presidential Library in College Station, Texas.

Mr Bush served two terms as vice president under fellow Republican President Ronald Reagan before his own stint in the Oval Office from 1989 to 1993, a time that saw the end of the Cold War as well as the United States’ routing of Iraqi President Saddam Hussein’s army in the 1991 Gulf War.

He failed to win a second term after breaking a no-new-taxes pledge.

Mr Trump has ordered the federal government to close on Wednesday and both the New York Stock Exchange and Nasdaq will also be closed in observance.

Tweet from @jgm41

US bond and options markets were also due to be closed, with energy and foreign exchange markets expected to remain open.

Remembrances to George and Barbara Bush sprang up in the neighbourhood where he made his home, at a memorial at a city park and at the airport named in his honour.

Christy Smith paused over the weekend to pay her respects to Mr Bush at a bronze statue of him at a Houston park.

“He set a good example for all of us,” said Smith, 39. “He always was caring and treated people equally.”

-with AAP