US President Joe Biden boards Air Force One on April 14, 2022.
CNN  — 

President Joe Biden and first lady Jill Biden boarded Air Force One around 6:15 p.m. ET Tuesday evening for a roughly 30-minute flight to their hometown of Wilmington, Delaware, landing with a little over an hour to spare before polls closed in the Delaware primary.

Asked about the purpose of his trip, added to his public schedule at the last minute, the President said he was there “to vote.” Moments later, he and the first lady entered the Laird Performing Arts Center at the Tatnall School, cast their ballots and promptly departed.

They were in the air, headed back to Washington, before 8 p.m.

The trip, which came at the taxpayers’ expense, has raised questions about why Biden did not vote absentee, early or by mail. It involved two military flights, two presidential motorcades and protection by law enforcement agencies in two states and the District of Columbia.

Though the laws recently changed, Delaware now offers both absentee voting, which requires an excuse, and voting by mail, which does not. The President spent last weekend in Delaware after arriving there on a Friday afternoon.

While in Delaware on Tuesday, Biden declined to answer questions about why he chose to vote in person.

A sample ballot for where Biden lives shows that there is only one primary he can vote in on Tuesday, the race for state auditor, which involves an incumbent who was convicted over the summer of official misconduct and conflict of interest.

Incumbent Kathy McGuiness, a Democrat, was convicted over crimes centered on hiring her daughter to work for her office. McGuiness faces off against Lydia York, who has been endorsed by the Delaware Democratic Party, in the primary.

When the endorsement was issued in July, State Party Chair Betsy Maron said York’s candidacy was “an opportunity to restore the Auditor’s office to its intended function and do away with the political theater that has kept the incumbent at center stage for all the wrong reasons.”

Biden has flown home to Delaware frequently during his presidency, spending more than a quarter of his tenure at one of the homes he owns in the state. Still, his up-and-back journey on Tuesday evening was an unusual jaunt even for him.

Biden could have voted early in-person at a number of polling locations during one of the days he recently spent in the state. A search of the Delaware voter website shows five early voting sites listed for the President’s address that were open from August 31 until September 11.

In the 2020 presidential election, the Bidens voted early in person on October 28, a week or so before Election Day.

Delaware has also recently eased some rules on voting remotely. A new bill signed into law this summer allows for voting by mail without an excuse.

Instead, Biden made the separate trip to Delaware to vote, a journey that involved two 30-minute flights aboard the military version of a Boeing 757.

The costs of flying Air Force One have been difficult to discern in the past, though some figures have placed the total at more than $100,000 per hour. On Tuesday, Biden flew in a smaller plane than the usual modified Boeing 747.

Coming an hour after hailing the highest-ever investment in combating climate change during a ceremony for the Inflation Reduction Act at the White House, the trip also raises questions of carbon footprint.

Presidents often prefer returning to their home states to vote, though have cast absentee ballots in the past, particularly for primary elections.

President Donald Trump, who questioned the security of absentee or vote-by-mail ballots, nonetheless voted absentee in municipal elections and congressional primaries in Florida. However, instead of mailing his ballot, he had a representative return his completed ballot.

President Barack Obama, meanwhile, sought to promote early voting by casting his ballot ahead of Election Day in 2016. He returned to Chicago to vote in early October.

CNN’s Kaitlan Collins contributed to this report.