Buckle up for some light turbulence.

The company of GOP Missouri Senate candidate John Brunner, Vi-Jon Inc. LLC, was late in paying local property taxes on its private plane in 2006, according to tax records obtained from the St. Louis County Department of Revenue.

Brunner was CEO of the company at the time. Vi-Jon, a cosmetics and health care products manufacturer, paid $697 in interest and penalties on the late taxes.

The revelation of the late taxes, first reported by Politico, probably eliminates — or at least undermines — a potent talking point for Republicans, who were merciless in skewering Sen. Claire McCaskill (D) for tardiness in paying taxes on her now-sold private plane.

“2006 was the first year that Vi-Jon owed property tax on the company plane and the company’s tax advisers unfortunately missed the filing deadline for that year,” Brunner’s communications director, Todd Abrajano, said in a statement. “The oversight was corrected 68 days after the deadline and all taxes, penalties, and interest were paid in full.”

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Brunner’s campaign knocked McCaskill for her plane tax mishap as recently as February.

“Claire knows that mistakes can be embarrassing,” said McCaskill’s communications director, Caitlin Legacki, in a statement to Roll Call. “But Claire also understands that true leadership is taking accountability for honest mistakes and fixing them, not finding someone else to blame.”

Brunner faces a competitive primary next month against former Missouri Treasurer Sarah Steelman and Rep. Todd Akin. A recent Brunner poll had him ahead of him competitors.

While McCaskill is one of the most vulnerable incumbent Senators in the country, GOP observers continue to see the Missouri Republican field as less than stellar. And the revelation about Brunner’s company’s tax mishap gave Democrats reason to crow today.

“Watching the Republican primary in Missouri is like watching the clown cars at the circus,” a Democratic operative familiar with Missouri said. “And as we head toward the August election, it’s turning out to be a race of who doesn’t screw up quite as bad as the other two.”

Roll Call rates the race a Tossup.