Indiana Gov. Mitch Daniels (R) will greet President Obama on the airport tarmac when he arrives in Indianapolis for an event Friday at a transmission plant.

It's Daniels's latest gesture of civility toward the president, something rare among those in his party considered to be potential White House challengers. The two-term governor of Indiana has told his fellow Republicans to "stop whining" about the Obama administration. Asked recently whether he thought questions about Obama's natural-born American citizenship were relevant, Daniels didn't hesitate. "I don't," he said.

"The American people that elected President Obama had a chance to weigh it at the time," the governor added. "I have my differences with the president, but they have nothing to do with things like that."

Obama is set to tour an Allison Transmission manufacturing plant before speaking to workers there. It's his second trip to a battleground state since he filed his reelection paperwork on Monday. 

The president traveled Wednesday to Pennsylvania, another state he won in 2008. Both trips have seen Obama address energy issues.