Less Fewer than half of the Air Force's combat-coded squadrons are fully prepared for combat, top service officials told lawmakers on Wednesday.

"While the specific numbers are classified, I'll tell you the overall combat capability of our combat coded squadrons in the Air Force is still below 50 percent, so fewer than 50 percent of them are fully combat capable – but it is rising," Chief of Staff Gen. Mark Welsh told the defense subcommittee of the Senate Appropriations defense subcommittee on Wednesday.

However, tThe Air Force's proposed budget for fiscal 2016 does not include the steep Budget Control Act spending cuts called for by the Budget Control Act of 2011, which could return next fiscal year unless Congress repeals the mandated spending caps.

If the Air Force has to return to Budget Control Act funding levels, the decline in squadrons that are fully combat ready will be "stunning," Welsh said.

"It will not be a precipitous drop off because we will prioritize funding for readiness, but we will not be able to continue the recovery of individual and unit readiness that we had started over the last two years," Welsh he said.

Welsh said tThe Air Force also faces a bigger problem because it has not invested in training ranges and other infrastructure over the last 15 years, Welsh said. It will take between eight and 10 years for the Air Force to rebuild that infrastructure, depending on how much money it gets.

The Air Force was hit hard by the Bbudget Control Act cuts known as sequestration, which went into effect in 2013 when Congress and the president failed to reach an agreement on how to balance taxes and spending.

Because the cuts came in the middle of the fiscal year, the Air Force had to take drastic measures to reduce spending, including such as slashing flying hours. Ultimately, the service had to ground 17 combat squadrons that year.

In 2013, the Air Force also had to cancel two Red Flag exercises, which simulate air-to-air combat, and along with four Green Flag air-to-ground combat training exercises. A weapons school class at Nellis Air Force Base, Nevada, was also canceled.

Air Force Secretary Deborah Lee James said she is concerned that roughly half of combat air forces are not sufficiently trained for "high end" combat.

"I'm talking about a conflict in which the enemy has the ability to interfere with you in the air or in space," James told reporters after Wednesday's hearing. "So this would integrated air defenses; this would be surface-to-air missiles, that sort of thing."

While the Air Force would be prepared if it was called on to fight a high-end war, the service has to get more squadrons fully combat ready, she said.

"I want to make sure that we are readiest that we can be and ought to be and I think we can do better in this country than what sequestration would allow for us," James said.