The conservative government watchdog Judicial Watch FOIAed the US Air Force for information about the June 2011 trip to Africa by First Lady Michelle Obama and Sasha and Malia Obama and today issued a press release about the trip.

The White House says a number of assertion made by the group are in error.

To wit:

The group calculated that the use of the C-32A aircraft cost taxpayers $424,142 (34.8 flight hours x $12,188 per hour).

“The number stated is misconstrued and out of context,” says a senior White House official. “The hourly rate is not the marginal cost of operating the plane — it is an accounting figure that prices in a number of fixed costs from maintaining the Air Force fleet for this kind of plane over a year. For example, it includes estimated replacement parts, depreciation, repairs, and costs that would have been incurred regardless of this flight.”

Judicial Watch says that Sasha and Malia Obama are listed as “Senior Staff.”

Not true, says the White House.

“The Obama daughters were not listed as Senior Staff – that only designates the area of the plane where they were seated,” says the official. “The Air Force categorizes the passengers by compartment on the plane.”

The conservative group noted that the “trip ended with a private family safari at a South African game reserve before the group returned to Washington on June 27,” with Judicial Watch President Tom Fitton saying in a statement “This trip was as much an opportunity for the Obama family to go on a safari as it was a trip to conduct government business.”

The senior White House official says that private safari “was designated as a private event and paid for personally,” and argues against any suggestion that this trip was a vacation. “It was an official trip with a 5-7 official events each day,” the official says.

-Jake Tapper