In what appropriators are calling a “disturbing” development, lawmakers say the Air Force has diverted over the last two fiscal years nearly $1.3 billion from funds to train pilots overseas without telling Congress.

The Air Force’s decision to tap the training funding, which is about a quarter of the money in those accounts, for other purposes follows years of military complaints about lacking adequate and predictable resources to properly train pilots and other personnel.

“The review of the fiscal year 2020 budget request uncovered some disturbing data points that have called the budget formulation process for flying hours in the overseas contingency operations (OCO) request into question,” appropriators said in the report accompanying the compromise fiscal 2020 Defense spending measure released Monday night.

The Air Force moved just under $1.3 billion in fiscal 2018 and 2019 to “unbudgeted expenses,” according to the report. Appropriators did not elaborate on where the Air Force moved the money.

The Air Force has congressionally approved procedures for redirecting money as needed, but the service did not follow them, the appropriators said.

“Frustratingly,” the conferees wrote, “it was only after the fact that the congressional defense committees found out what was purchased with the asset [sic] provided from the flying hour account.”

The conferees responded by subtracting fully $400 million from the $6.5 billion request in fiscal 2020 for Air Force flight training overseas.

“The fact that the Air Force has moved roughly 25 percent from the OCO flying hour funding request for each of the past two years indicates more of a fundamental issue with the initial request as opposed to an anomaly,” the conferees said. “Therefore, the agreement includes a new reduction to the Air Force OCO flying hours funding request to more closely align with historical execution.”

The Air Force did not respond to a request for comment.