Republican presidential candidate Mitt Romney promised that if elected, he would restart production of Lockheed Martin’s F-22 Raptor stealth fighter. “I would add more F-22s,” the former Massachusetts governor said in Virginia on Saturday. Don’t buy it.

The plan, if you can call it that, is totally possible. But just because a Raptor resurrection is possible doesn’t mean it’s realistic — let alone a good idea.

It’s actually easier to return the F-22 to production than it is to restart most discontinued warplanes. Lockheed and the Air Force carefully preserved all the tooling and blueprints to make the radar-evading jet. Usually, warplane manufacturers usually dismantle the bulky factory tooling once production wraps on a particular model. Still, reviving the F-22 would cost billions before a single new jet even entered production. It would also upend the Air Force’s carefully laid plans for producing new drones, tankers, bombers and — oh yeah — the cheaper and arguably more capable F-35 Joint Strike Fighter.

It’s not clear how serious Romney is about his proposed Raptor re-start. According to Time, Romney mentioned the idea at a rally in the “rather modest” Military Aviation Museum outside Virginia Beach. “Perhaps he was just channeling the good vibes he was getting from all the museum pieces,” Time quipped.

Building more Raptors is not impossible. As production of the last of 196 F-22s ended at Lockheed’s Marietta, Georgia plant in December, the company packed all the specialized machinery — 30,000 items in all — into air-conditioned shipping containers and sent them to the U.S. Army’s Sierra depot in northern California for long-term storage. To preserve production techniques, Lockheed photographed and videotaped workers at their stations and transcribed worker testimony, programming the resulting information into 80 iPad-like devices encompassing all aspects of Raptor assembly.

Officially, the Air Force wants F-22 production materials preserved so it can make new spare parts for the existing stealth fleet. In past years the flying branch had fought for more Raptors — 243, to be exact — but in 2009 former Defense Secretary Robert Gates held the line at 187 plus nine prototypes — and President Barack Obama signed off on the lower number. “There’s no chance of revisiting that decision,” Gen. Norton Schwartz, the recently retired Air Force chief of staff, said in July.

What would it take to bring back the F-22? “In a national emergency, I would say anything is possible,” Schwartz said. Lockheed could retrieve the shipping containers, set up a new factory somewhere (the old F-22 assembly plant is now building cargo planes) and bring back Raptor workers, most of whom are still with the company.

In 2010 the think-tank RAND estimated it would cost an extra $90 million per plane, on top of the existing $137 million price tag per plane, to restart production and build 75 more Raptors following a two-year shut-down. But Romney’s F-22 v2.0 would begin assembly in 2013 at the earliest, meaning the restart would be at least a year later than RAND’s model and costs would surely be higher. The Air Force bought most of its Raptors in annual lots of around 20 jets. If a Romney administration bought a batch in each of its four years, the total cost for up to 80 new F-22s could top $20 billion.

That might seem like a lot, but Romney’s F-22 numbers do add up … in the abstract. The candidate has proposed spending 4 percent of U.S. gross domestic product on the military, which amounts to adding at least $100 billion a year to the Pentagon’s current $500-billion-plus budget. Romney’s defense plans involve adding another 100,000 active-duty troops, requiring some $25 billion annually; and an boosting Navy shipbuilding by six new ships a year, costing probably $8 billion combined annually. More Raptors could easily fit within the remaining $65 billion per year Romney said he would add to Pentagon coffers, with plenty of money left over to staff and operate the new F-22 squadrons.

The problem is, the Romney budget scheme is itself looks like wishful thinking, particularly in light of the candidate’s pledge to reduce taxes below today’s modern lows and still erase a trillion-dollar annual budget deficit. “If you pursue this, how are you going to balance the budget?” Lawrence Korb, a defense wonk at the liberal Center for American Progress, said of the Romney defense plan.

In the real world, it’s unlikely Romney’s grand budget scheme would receive congressional backing. A Romney administration could probably boost defense spending somewhat, but $100 billion per year seems like an unrealistic figure. In that case, F-22s seem a lot less affordable — unless Romney is prepared to revise the Air Force’s stated priorities.

Of all the hardware the Air Force is buying, at a cost of around $40 billion a year, the most urgent is the new KC-46 tanker, followed by the F-35; drones; a new stealth bomber; and satellites, according to the flying branch. The tanker is already running over budget, the F-35 has run out of cash reserves and the bomber is at serious risk of a multi-billion-dollar cost overrun. Drones and satellites have budgetary problems, too. There’s not a lot of room to slip in $5 billion a year in F-22s without jeopardizing other production lines.

It’s not clear the Air Force would want to displace its current in-production fighter, the F-35, with the revived F-22. For all its stealth, speed and agility, the F-22 has drawbacks. For one, it might still be choking its pilots owing to apparent faults in the pilots’ vests or the jet’s oxygen system. Moreover, the Raptor lacks modern datalinks for securely swapping information with any other aircraft besides another F-22 — a weakness that forced the Raptor to sit out the Libya war. The F-35 has none of those flaws, though it has plenty of of problems of its own.

Most importantly, at $110 million per copy the F-35 — even though it’s the most expensive weapon program in human history – is cheaper on a unit basis than the F-22. And the Air Force is gearing up to buy many, many more of them: 1,763, enough to replace all of today’s aged F-15s and F-16s. The F-35 “is our future,” Lt. Col. Lee Kloos, commander of the first F-35 training squadron, remarked on Tuesday.

Not so much the F-22 — regardless of what Romney says.