President Obama returned to the campaign trail Thursday, launching his final pre-Election Day push with a whirlwind 24 hours that will put him in all four of the continental U.S. time zones.

Republican presidential nominee Mitt Romney spent the day in the battleground state of Virginia, where he hammered home the central theme of his closing argument to voters: that he is a champion of business whose policies would usher in new jobs and rising incomes for America’s workers and entrepreneurs

“Today, we’re at the lowest level of new business start-ups in 30 years,” Romney said in a speech that repeated his recent mantra of “real change.” “So I want to change this dynamic and make business recognize they have a friend in Washington, not a foe.”

Obama kicked off his trip with a rally on the tarmac at the airport here in Green Bay, in the Central Time Zone, where he mocked Romney for offering himself as the candidate of change, stealing the mantle Obama used four years ago.

Romney is simply dressing up the policies used by former president George W. Bush, Obama told the crowd, the same ones that drove the country into a recession.

“Let me tell you, Wisconsin, we know what change looks like. What the governor is offering sure ain’t change,” Obama said.

Then he ticked off more policies he said Romney would pursue that did not represent change: rolling back Wall Street reform, giving a tax cut to the wealthy and overturning the Affordable Care Act, Obama’s signature health-care reform legislation.

“Turning Medicare into a voucher system is change, but we don’t want that kind of change,” Obama said. “After four years as president, you know me by now. You may not agree with every decision and you may be frustrated by the pace of change. But you know I will fight every single day for you and your families as hard as I know how.”

He added, “I know what change looks like because I fought for it. So did you. After all we’ve been through, we can’t turn back now.”

After wrapping up his remarks, Obama reboarded Air Force One to fly to Las Vegas (Pacific time). He was then scheduled to travel to Boulder, Colo. (Mountain time), then catch a few hours sleep in Columbus, Ohio (Eastern time), after arriving there at around 2 a.m. on Friday. The president is making up for lost time after he suspended campaigning on Monday to focus on the federal response to Hurricane Sandy, visiting New Jersey on Wednesday to join Gov. Chris Christie (R) in viewing hard-hit areas along the coastline.

“Even though this is President Obama’s last campaign, he’s fighting for the same things he’s always believed and run on — that this country cannot succeed without a growing, thriving middle class,” campaign spokesman Adam Fetcher said in a statement.

“Middle-class security — which has been undercut by the policies and decisions of the last decade — is what’s at stake in this election, and the president will talk about our fight to reclaim it.”

Obama has sought to define the election as a choice between his and Romney’s contrasting visions on how to boost the economy and create jobs. The president has emphasized investing in education and infrastructure, while Romney has focused on reducing spending and the federal debt.

Although unemployment dipped to 7.8 percent last month, the first time it has been below 8 percent during Obama’s tenure, the recovery has been tenuous. On Friday, the Labor Department will release its October jobs report, just four days before voters head to the polls.

The Obama campaign unveiled a new television advertisement Thursday featuring former Secretary of State Colin L. Powell, who served during both Bush administrations but endorsed Obama in 2008 and again this year.

“When he took over, we were close to a depression,” Powell says in the ad. “And I saw over the next several years stabilization come back.”

In his whirlwind Thursday jaunt, Obama will visit four of the seven most critical swing states.

He will hold his first event in Wisconsin (Central Time Zone), a state that has become especially competitive since Romney added Rep. Paul Ryan (R-Wis.) as his vice-presidential running mate. Polls show a tight race in a state the president won easily in 2008.

Aboard Air Force One en route to Green Bay, Obama campaign spokeswoman Jen Psaki was asked if the campaign had regrets that the president did not spend more time early on campaigning in Wisconsin.

“We always knew this state would be harder than it was for us in 2008,” she said. “Obviously when Mitt Romney chose Paul Ryan as his running mate, he’s a native son. He’s basically moved into the state and put a great deal of time in there. . . .We’ve had an organization on the ground there since 2008 and we think that continues to be helpful and is one of the reasons we’re going to win Wisconsin on Tuesday. We certainly don’t look back and have any regrets.”

Obama’s decision to spend the night in Columbus emphasized that the city is perhaps the most important battleground state in the 2012 election and a near must-win for both campaigns.

Obama is expected to carry the northern part of Ohio, including voter-rich Cleveland, while Romney is expected to outpace him in the southern portion around populous Cincinnati. But in the purple mid-section around Columbus, the two candidates are battling for every vote. Each has been pouring vast sums of money into television advertisements and gearing up their ground games to get out the vote Tuesday.

Romney, who joined Ryan on a bus tour through Ohio this week, has been criticized for airing television ads in the state that inaccurately portrayed the effects of the Obama administration’s automaker bailout.

Obama will hold three rallies in Ohio on Friday before briefly returning to Washington. He will go back to Ohio on Saturday. The president is scheduled to continue campaigning Sunday and Monday, and he plans to spend both of those nights in his home town of Chicago, where he will join supporters Tuesday night at a watch party at McCormick Place’s Lakeside Center.