DES MOINES, Iowa (CNN) -- Arizona GOP Sen. John McCain's "Straight Talk Express" - the 2008 version - set out on a bus tour of Iowa Thursday.

At a news conference in Des Moines, McCain rejected the notion that he could not maintain the "maverick" status he earned during his first run for president in 2000.

"I'm still the same candidate, we're still having fun, we're still on the bus," he said. "I am convinced we are doing fine will do just fine."

In an e-mail to supporters Thursday, McCain praised the "Straight Talk Express" as a symbol of a "new type of politics in America, an unfiltered discussion on any topic of the day in an environment where politicians leave the spin at the door."

In Des Moines, McCain also reiterated his support for the president's plan to send more troops to Iraq.(Watch Video: McCain talks Iraq on Senate floor Wednesday)

"I am still convinced withdrawal means chaos," he said, "and if you think things are bad now, if we withdraw you ain't seen nothing yet."

McCain heads to town-hall meetings in Ames and Mason City, Iowa.

-- CNN Senior Political Producer Sasha Johnson