Biden and future first lady Jill Biden arrived at Joint Base Andrews shortly before 4 p.m. Tuesday.

They boarded their flight to Washington, D.C., from New Castle County Airport in Delaware and departed shortly after 3 p.m.

In Washington, the Bidens, as well as Vice President-elect Kamala Harris and her husband, Doug Emhoff, will take part in a national COVID-19 memorial service at the Lincoln Memorial Tuesday evening to honor the 400,000 Americans who have lost their lives to the virus.

-ABC News' Molly Nagle and Ben Gittleson

Biden delivered short but emotional farewell remarks in a send-off event in Wilmington, Delaware, on Tuesday afternoon, and wiped away tears as he wished his adopted state -- which first elected him to U.S. Senate at the age of 29 -- goodbye.

Apologizing for his emotions, Biden said he'll always be "a proud son of the state of Delaware."

"Excuse the emotion, but when I die, Delaware will be written on my heart," Biden said, choking up.

Biden also recalled a story he often shared on the trail, noting the historic nature of his time as vice president, serving alongside the nation's first Black president and now being a part of another historic feat, being inaugurated with the country's first Black female vice president, saying, "That's America," to applause.

In another emotional moment, Biden said his only regret was that his late son, Beau Biden, wasn't there with them. The location Biden spoke at, the Joseph R. "Beau" Biden III National Guard/Reserve Center, was named for his son, who died of brain cancer in 2015.

"Ladies and gentlemen, I only have one regret, that he's not here, because we should be introducing him as president," Biden said.

Beau was 46 when he died, and Biden is hours away from being sworn in as the 46th president of the United States.

"I know these are dark times, but there's always light. That's what makes this state so special. That's what it taught me, it taught me the most -- there's always light," Biden told the small crowd of supporters.

Before he spoke, he gave a masked kiss on the cheek to his sister, Valerie Biden-Owens, who he has often described as his best friend, and during his remarks referenced all of the Biden family members who were in the crowd, including his son Hunter Biden, his wife Melissa, their young child, and Biden's grandchildren: Naomi, Finnegan, Maisy, Natalie and Hunter.

-ABC News' Molly Nagle

Secretary of State Brad Raffensperger has certified the results of the Jan. 5 runoff election, according to a press release.

The certificates of election must now be signed and issued by Gov. Brian Kemp. A representative for Kemp must then physically deliver those certificates for Rev. Raphael Warnock and Jon Ossoff's victories to the secretary of the Senate, per Senate rules, triggering the swearing-in process.

On Wednesday after her own swearing in, then-Vice President Kamala Harris will swear-in Warnock and Ossoff, as well as the successor to her California Senate seat, former California Secretary of State Alex Padilla, according to a Harris aide.

Once the certificates are delivered and all are sworn in, Senate Minority Leader Chuck Schumer will be handed the reins as majority leader.

-ABC News' Quinn Scanlan and Averi Harper

Outgoing Senate Majority Leader Mitch McConnell, in what could be his last floor speech as majority leader, placed blame on Trump for inciting the mob of rioters who attacked the U.S. Capitol on Jan. 6.

"The mob was fed lies. They were provoked by the president and other powerful people," McConnell said from the Senate floor Tuesday.

His remarks come six days after the Democratic-led House impeached Trump on one charge of "incitement of insurrection" and after McConnell indicated he was weighing whether to vote to convict Trump.

McConnell also affirmed that Biden and Harris will be sworn into office Wednesday and urged a bipartisan path forward.

"Americans elected a closely divided Senate, a closely divided House and a presidential candidate who said he'd represent everyone. So our marching orders from the American people are clear," McConnell said.
-ABC News' Allison Pecorin

In his appearance on ABC's "This Week" Sunday, Biden’s nominee for Surgeon General Vivek Murthy said that when it comes to meeting the goal for 100 million vaccines in the first 100 days of the president's administration, there are things that could go right or wrong.

"I think President Biden fully understands there's a larger goal here, as we all do, which is that we've got to vaccinate as many Americans as possible. And that's going to take a lot of work, work dispelling this disinformation, working on the supply, increasing distribution channels," he told ABC News Chief Anchor George Stephanopoulos. "And that's some of what the vaccine plan that he announced over the last week is intended to -- to achieve."

Stephanopoulos pressed Murthy on whether there are ways to increase the supply and equitably distribute the vaccines.

"It appears, at least in these first vaccines that have gone out, they've been going largely to wealthier areas of the country, largely to whiter areas of the country," Stephanopoulos said.

"Well, it's the right question, George, because success has to be gauged not just by the number of vaccines we deliver but also by how fairly we deliver those vaccines -- how equitably we deliver them," he said in response. "What we've got to do here is not just, again, increase supply, which we can do using the Defense Production Act ... but we've also got to set up the kind of distribution channels, like mobile units, like strategically placed community vaccination centers, that can reach people who traditionally are hard to reach and don't have access to health care."

He added, "We have got to track our progress. We have got to make sure that we have data on where the vaccine is being administered, so that we can ensure that it, in fact, is being distributed equitably."