Air Force leaders are bracing for an extended continuing resolution in Congress, which would keep the military services' spending capped at last year's budget levels.
One of the first things that would be cut? Flying hours.
Vice Chief of Staff Gen. Stephen Wilson said the Air Force is trying to "solve a $1.3 billion math problem by late April."
"It will force us into actions similar [to those] taken in 2013 for sequestration," Wilson told audience members during the McAleese defense conference in Washington, D.C., earlier this week.
"I'd have to stop flying sometime this summer," Wilson said. "I would have to shut down some hiring at our depots, and only fix things at our installations if they broke. That's what a one-year-long CR does to us."
The stop-gap funding measure also prevents the start of 60 new programs without an appropriations bill from Congress.
Wilson said that's at least $500 million worth of flying hours, or about two months of flying time.
"All of this affects readiness, the very thing we're trying to fix right now," he said.
In fiscal 2013, the Air Force had to stand down 17 combat squadrons, which came as a surprise because officials thought it "wasn't going to happen," then-Air Combat Commander Gen. Herbert "Hawk" Carlisle said in 2015.
"We didn't start [the cuts] until halfway through the year," he said at the Air Force Association's Air Warfare Symposium in Orlando at the time, as reported by Air Force Times.
While Pacific Air Forces and U.S. Air Forces Europe-Africa were largely unaffected in their flight time, they did have to cancel exercises with other countries, service officials said at the time.
And that's what generals such as Air National Guard Director Lt. Gen. Scott Rice are preparing for now when deploying Guard members for temporary assignments overseas with active-duty airmen, or even for stateside exercises.
"There's a way that I save money in my program because I have a part-time, full-time mix," Rice told Military.com on Wednesday. "I put the part-time force … their piece is two weeks a year, one weekend a month -- we do a lot more than that -- but the two weeks a year tends to fall into the summer [exercises]," he said.
Guard members could normally see a temporary duty, a flag exercise, or even smaller exercises at combat readiness training centers, Rice said.
"So I take risk in those deployments if I have a CR where I don't get all that funding, so I will lose training in the summer time -- not from flying hours as much as I do from my TDY deployments," he said. "This affects all of us."
Leaders in both the House and Senate have until April 28 to extend a stopgap spending measure CR or approve a full-year appropriations bill.