Half of the combat Air Forces are "not sufficiently ready" for a high-end fight against an opponent with strong air defenses, said Air Force Secretary Deborah Lee James, adding that the Pentagon needs to emphasize training to make sure all airmen are prepared should an engagement arise.

"A high-end fight is the type of fight where the enemy on the ground can interfere with you, can shoot you down," James said Tuesday evening. "A high-end fight is a fight where you might go up against integrated air defenses and surface-to-air missiles. We have not been tested in the real world for such a fight for quite some time."

Speaking at an event hosted by Bloomberg Government, James said she believes the Air Force has made good investments in technology and equipment to prepare for such a fight, including fifth generation fighters like the F-35 and F-22.

But in recent years, the Air Force’s mission has been focused on Close Air Support close-air support and bombing terrorist targets with little aerial resistance. James said she believes training is suffering as a result, and that more investment needs to be made in preparing pilots and maintainers for any type of engagement — including those against nations who possess more advanced air defenses than Al Qaeda al-Qaida or the Islamic State group.

The secretary said it was "very worrisome" that she is hearing from combatant commanders that many airmen are under-trained for an engagement against a target with hardened aerial defenses.

Indeed, many members of the Air Force have joined since Sept. 11, 2001, and have known few operations other than the service’s missions in Afghanistan, Iraq, and Syria.

James said airmen need more training, but that the current high operational tempo is preventing that.

"You have to free up your people to get away from the work of today and you've got to get them through this training pipeline," she said. "This is the part where we have simply not been able to free them up in sufficient numbers. They're so dog-gone busy in the Middle East or the Pacific or doing the reassurance in Europe."

An increase in end-strength could certainly help address personnel and training issues, the secretary said, but that’s at risk if Congress fails to pass a budget or only passes a Ccontinuing Rresolution that would fund the Pentagon at FY 2015 levels.

James said she believes a shutdown has been averted but "wouldn't necessarily bet the farm on it, yet."

"Every time I think I have it figured out, there is some new twist, some new development," said James, who spent 10 years working as a staffer for the House Armed Services Committee.