Ex-Sen. Scott P. Brown may not have officially announced his candidacy for New Hampshire’s Senate seat, but former Sen. Bob Smith has — sort of.

The Republican lawmaker has filed papers for the New Hampshire Senate seat he held for 12 years — though he hasn’t exactly announced his candidacy formally.

He is, however, hitting the D.C. circuit in search of money and support. And HOH had the unplanned pleasure of sitting next to him on his return flight from Baltimore to Manchester, N.H., on Thursday.

If you ask Smith, he has every intention of beating sitting New Hampshire Democrat Jeanne Shaheen and fellow Senate alumnus Brown.

“I’m not running for my health. I’m serious,” Smith told HOH over the course of a roughly 45-minute discussion that ranged from the current race to the sheer magnitude of the universe. (He couldn’t seem to shake a recent Discovery Channel special on the solar system.)

I was seated next to Smith by chance and initially listened to him discuss some internal strategy with his campaign manager, Sam Pimm, before revealing myself to be a reporter.

Smith had spent the previous night at a fundraiser with about 40 people — a detail he and his campaign manager were contemplating leaking to New Hampshire political reporter John DiStaso of the Manchester Union Leader — and he and Pimm were discussing such practical matters as buying a campaign van in place of a bus to save money.

Smith made it clear, throughout the course of the conversation, that his conservative principles applied just as much to his campaign as they do to his politics. Smith, off the top of his head, was able to provide price quotes for the various flights to New Hampshire that night — hence the reason he was taking a Southwest flight out of Baltimore and not the pricier, but more convenient, trip from Ronald Reagan National Airport.

He also acknowledged that Brown and Shaheen will have more money in the race, but noted that he’d been outspent in races before and still won because of a superior ground game.

Smith didn’t seem scared of a bruising GOP primary with Brown. In fact, his initial reaction was to joke about it.

“Who?” he asked facetiously.

“We’re running. That’s his decision to make,” Smith said of Brown’s nebulous position.

He suggested that the race between himself and Brown was one between a moderate and a conservative — something that didn’t typically end well for the more moderate primary contender.

Smith also questioned Brown’s motives for office, noting that Brown declined to run for governor of Massachusetts because he said he wanted to spend more time with his family.

But Smith also expressed a desire to keep the race about policy, not personalities.

He refused to call Brown, who recently moved from Massachusetts to New Hampshire, a “carpetbagger.” Smith himself has run for Senate twice in Florida, once in 2004 and then again in 2010.

Per Smith, this race is really about Obamacare — the issue that seemed to motivate him to run for Senate again.

He spoke at length about the health care overhaul’s effect on medical innovation in the United States, and joked that even though it was a “trite” exercise to call the impending election the most important one in American history, it might actually be true in 2014.

Smith also had some choice words for the current state of Congress. He bemoaned the “bastardization” of regular order and showed some disdain for the current crop of junior Republicans, including Sens. Ted Cruz of Texas, Mike Lee of Utah and Rand Paul of Kentucky.

“The Senate is not designed for people who are impatient, unfortunately,” he said.

Smith said he didn’t know what committees he’d want to serve on if he were elected, but he’d likely have some latitude to decide, given his seniority within Congress. He said he wanted to avoid the Appropriations Committee because they spend money, something he remains averse to as a conservative. The assignment that seemed most appealing is his former post on Armed Services.

Committee spots are the least of Smith’s worries. A recent poll found Brown well ahead of Smith and other contenders in a theoretical GOP showdown.

But, as Smith noted, the New Hampshire primary — scheduled for Sept. 9 — is still “insanely” far off.