Former President George W. Bush, the eldest of the four Bush sons, and his wife, Laura, along with brother Neil Bush and his family, boarded the plane for the cross-country trip to Joint Base Andrews outside Washington.
With hands on hearts, members of Bush's cabinet, lawmakers and Supreme Court justices honoured the 41st president as his flag-draped casket entered the Capitol Rotunda.
Bush's death has also led to a series of symbolic moments.
Mayor Sylvester Turner is hosting Monday evening's event featuring music and community leaders in front of City Hall.
The funeral at the Washington National Cathedral, set to be attended by a wide array of former presidents and politicians, including Donald Trump, will last 90 minutes.
Spokesman Jim McGrath tweeted Monday that Bush "will be carried to his final rest" wearing gray socks saluting the Armed Forces and paying "tribute to his lifetime of service", starting as an 18-year-old "naval aviator in war".
The former president's remains will be flown to Washington, D.C. on Monday following a departure ceremony in Houston, Texas. Bush was a humanitarian and made volunteerism a hallmark of his presidency from 1989 to 1993.
He said Bush was the first president he ever voted for and was "the first president to teach me and many of us that in a democracy sometimes you fall short", and how you handle that, "is just as important as how you win". Wednesday has been designated by President Trump as a national day of mourning, and most federal agencies will be closed with federal workers given the day off.
Following the service at the National Cathedral, Bush will be flown to Houston on Wednesday with a scheduled arrival of around 4:30 p.m. CST.
After, he will lie in repose at Houston's St. Martin's Episcopal Church before his remains are transferred via rail to the Bush Presidential Library at Texas A&M University, where he ultimately will be buried. His body will then be transported by a special train to its final resting place, the Bush Presidential Library in College Station, Texas.
Use the hashtag#Honoring41 to share your memories/photos of#Bush41. Barbara Bush died on April 17 at their Houston home.
The German government press service announced Monday that German Chancellor Angela Merkel will fly to Washington, DC, to take part in the memorial service for the late president, who oversaw the end of the Cold War and the reunification of Germany.
Spent a wonderful day at College Station back in 2011.