LAKELAND, Fla. – Republican presidential nominee Mitt Romney urged Americans to “hold us accountable” as he and running mate Rep. Paul Ryan (Wis.) sought to capitalize on momentum coming out of their convention by stumping through key swing states.

Romney and Ryan rallied hundreds of supporters on an airport tarmac in Lakeland before splitting up in their new logo-bearing campaign planes.

Romney said President Obama has not delivered on his campaign promises of four years ago, then laid out a five-point plan of his own to improve the economy.

“We’re going to go after these things,” Romney said. “Measure us. Hold us accountable. Do the same with the president. Look, you’re making a choice as to who the servant’s going to be for the nation. Who is the person, who are the people who will lead this country and do what you want to be done?”

“You listened to the last guy running for president,” Romney said, referring to Obama. “He laid out what he would do; he was unable to do it. It’s time to give someone new a chance. Hold us accountable. Listen to what we have to say and say do I want that or not.”

Romney said he was “embarrassed” by warm comments made about him at Thursday night’s program at the Republican National Convention, which included moving personal testimonials as well as his own at-times emotional acceptance speech.

“So last night you got to know me a little better with some friends that talked about my life, the things that have been part of my life in the past,” Romney said in Lakeland. “I talked to you a little bit about my family and I was embarrassed from time to time with the nice things that were said. Some people were overly generous, but I appreciated it.”