The Air Force wants to grow from 55 fighter squadrons to 60 to keep up with the pace of combat operations, spokesman Col. Patrick Ryder said Tuesday.

In a gaggle with reporters at the Pentagon, Ryder said the Air Force had 134 fighter squadrons in 1991, the year of the Persian Gulf War, but today has just 55, although combat operations have continued at a strong pace. While the Air Force is still able to carry out its mission — most recently to strike the Islamic State militant group in Iraq, Syria and Libya — Ryder said it's taking a growing toll on airmen, their equipment and readiness.

Though the need to add force structure is clear, the Air Force has not set a timeline for how soon it would like to get to 60 squadrons, he added.

"The Air Force continues to remain the finest in the world," Ryder said. "However it's the smallest and oldest in our history, despite a continuing increased requirement for airpower."

Ryder also reiterated the Air Force's desire to eventually grow its active-duty end strength to 350,000 airmen, which he said is necessary to meet current national security requirements. The Air Force had more than 510,000 active-duty airmen in 1991, but had shrunk to 311,000 by the start of fiscal 2016 began. The service grew to 317,000 by the beginning of fiscal 2017, and is expected to hit 321,000 at the end of this year.

Ryder said the airpower-driven ISIS war shows the Air Force is still able to fight and win, but that a 317,000-strong active duty is "still far too small for the missions that we've been given."

Air Force officials said in December that they hope to reach an end strength of 324,000 airmen by the end of fiscal 2018, and 350,000 airmen by the mid-2020s. The growth would be focused on the maintenance, nuclear, cyber and space career fields, they said.

Of course, all this will require more money, and Ryder said the Air Force needs to close or consolidate excess infrastructure. A new Base Closure and Realignment Commission is needed, he said, noting that service leaders have repeatedly made that need clear. As just one example of how that could pay significant dividends, Ryder said consolidating bases would free up civil engineering units, now occupied with maintaining that excess infrastructure, to do other jobs, thereby reducing Air Force expenditures.

Congress has repeatedly ignored Air Force calls for a BRAC.