(AP Photo/Pablo Martinez Monsivais)

CLEVELAND - After 37 hours, 6,500 flight miles and six grassroots rallies that drew tens of thousands of supporters, President Obama's frenetic battleground-state blitz came to a close tonight with a rally on a small airport tarmac overlooking Lake Erie.

"This is the final stop on our 48-hour fly-around all across America. We've been going for two days straight," a visibly tired but spirited Obama told a crowd of 12,000 after taking the stage under starry skies.

"We've been from the East Coast to the West Coast and now we're going back east again," he said. "So Ohio, I gotta tell you, even though I've been going for about 38 hours straight, even though my voice is kind of hoarse, I've still got a spring in my step because our cause is right, because we're fighting for the future."

The event was marked by the dramatic arrival of Air Force One - the smaller Boeing 757-model - on a landing strip several hundred yards from where the crowd was huddled. The plane taxied right up to the stage and bleachers, which were lit by giant floodlights for Obama's final stump speech of his self-described travel "extravaganza."

The crowd chanted "Obama! Obama!" as the president jogged down the steps of his bird and out onto the stage.

"Hello, Ohio!" he said.

Over the past two days, Obama has crisscrossed the country, visiting Iowa, Colorado, California, Nevada, Florida, Virginia, Illinois and Ohio. He addressed 68,000 voters combined at rallies across the country and spoke to tens of thousands more by phone in conference calls from Air Force One.

He arrived here at Burke Lakefront Airport just hours after casting his own ballot in Chicago - the first time a sitting president has voted early in person for a general election campaign.

"I've come to Ohio today to ask you for your vote," he said. "And I'm asking you to vote early. Here in Ohio you can vote now. You don't have to vote later. I need you to vote now and I need your help to keep moving America forward."

Ohio is viewed by Obama strategists and the Republican nominee Mitt Romney's campaign as the decisive state in the 2012 election. President Obama has visited Ohio 18 times visit this year - making it his most-visited state of the election campaign, underscoring its importance.

"Ohio, I believe in you. And I need you to keep believing in me," Obama said. "And if you're willing to roll up your sleeves … we're going to win this election and finish this election."