The White House’s decision to fly a Marine helicopter to the South Lawn for an event highlighting American manufacturing last month cost taxpayers as much as $24,000, according to military records released to TIME.

The green-and-white Sikorsky VH-3D, known as Marine One when the President is aboard, was the centerpiece of the July 17 event at the White House showcasing American construction programs. President Donald Trump, Vice President Mike Pence and senior White House officials toured manufacturing products from all 50 states. The Connecticut-made helicopter was displayed alongside a yacht from Maine, a fire truck from Wisconsin, and a forklift from Mississippi.

The White House Military Office requested the helicopter’s presence in a fragmentary order, or FRAGO, barely 36 hours before the helicopter landed on the South Lawn for the “unusual” event, according to the records of Marine Helicopter Squadron One (HMX-1), the unit responsible for operating the helicopter.

“I just wanted you to make sure you were aware because it’s such an unusual high visibility event,” the commander of HMX-1 emailed his superior, the Marine Deputy Commandant for Aviation, the day before the event. The message indicated the helicopter would arrive on the South Lawn at approximately 7 a.m. on July 17 for the 3 p.m. event, and remain until the lawn was cleared between 6 p.m. and 9 p.m. that evening.

The note adds that should the departure from the White House be delayed, a second aircrew would be needed for the return flight due to duty-hour restrictions. The original flight crew was with the helicopter during the event, while unit security personnel remained with the aircraft while it was the ground. It was not clear from records provided to TIME whether a second flight crew was ultimately required.

The Hatch Act prohibits federal employees from using government property for political purposes. Records indicate that HMX-1 inquired about whether the event might violate the provision.

“One question we asked was if it was a violation of the Hatch Act and were informed it was not,” the commander wrote. “Sounds like you are locked, “the Deputy Commandant replied.

The “Made in America” event was designated an official event by the White House, and would not have been covered by the Hatch Act. But even official events have political overtones. At the event, the President made a push for healthcare reform efforts then underway in the Senate and touted efforts to rein in government regulations.

Using the aircraft known as Marine One or Air Force One for politically advantageous purposes is hardly a new phenomenon. Presidents are required to use them for travel. But requisitioning their use solely for a photo-op is unusual. Trump drew scrutiny in February when the presidential airplane taxied to the backdrop of his first campaign rally in Melbourne, Fla., and his Twitter account is flush with messages complaining about his predecessor’s use of the presidential aircraft.

“The White House is thrilled with the ‘Made In America’ showcase that featured products from all 50 states that are made by American workers with American materials,” said White House deputy press secretary Lindsay Walters.

HMX-1 crews frequently perform training flights around the Washington area and at the South Lawn to practice depositing the President of the United States at the White House with inches of precision. When Trump was at the G-20 summit in Germany in early July, HMX-1 conducted 58 practice landings at the White House. The flight for the Made in America event counted toward the aircrew’s training requirement for the month, an official said. Unit helicopters also flew an additional 11 hours that day for “non-presidential support missions.”

The White House said taxpayers did not pick up the burden for any of the other props featured at the event. A spokesperson for Sikorsky said the company was not involved in arranging for the helicopter to be displayed on the South Lawn.

HMX-1 doesn’t maintain budgetary records for presidential flights, and determining the precise cost incurred by the event is difficult. But according to Department of Defense hourly rates for fiscal year 2017, the DoD reimbursement rate for the VH-3D is $24,380 per flight hour. Unit records record the aircraft flight time as 30 minutes each way from its home base at Marine Corps Air Facility Quantico in Virginia.

The White House argues the true cost of operating the helicopter is well below that rate. “To place a cost to taxpayers based on the reimbursement rate estimates is highly misleading,” Walters said. “These rate estimates include personnel, maintenance and many other sunk costs that are included in annual appropriations.”

According to a 2015 RAND study, DoD reimbursement rates do not include the cost of personnel, but do account for fuel, maintenance, and contracting costs.

At the time, former White House press secretary Sean Spicer defended the use of the helicopter for the event. “The idea is to showcase this week things that are made in America,” Spicer said. “And I know Sikorsky and the state of Connecticut are very proud of the fact that they contribute to our national security, that there are, I assume, hundreds if not thousands of people whose job depends on that. And I think, like most Americans, we’re all proud of the helicopter and other military equipment that so many Americans worked tirelessly to do. So, of course, it’s appropriate to highlight that.”

It wasn’t clear whether Trump interacted with the helicopter as he toured the South Lawn for the event, but he did step into the driver’s seat of a fire truck. Inside the White House, Trump addressed Sikorsky representatives, joking with the media about his own fleet of company products. “I know Sikorsky very well,” the President said, “I have three of them.”

Contact us at letters@time.com.