The Navy's aircraft arsenal is so depleted it would take several years to rebuild the fleet even if the Trump administration allotted the funding needed to repair inoperable aircraft, according to a policy expert and former Air Force pilot.

John Venable, a senior research fellow for defense policy at the Heritage Foundation, cited a report released Monday that found two-thirds of the Navy's strike fighter jets are unable to fly due to maintenance problems exacerbated by several years of military budget cuts.

Thirty-five percent of grounded fighter planes are waiting for parts, while 27 percent are undergoing major depot work, according to the report published by Defense News. A full 62 percent of F/A-18 Hornet and Super Hornet strike fighters are out of service, a concerning figure because of the essential role the planes fill in the fleet's combat power.

In all, more than half of the Navy's planes are grounded, including some 1,700 combat transport aircraft, patrol aircraft, planes, and helicopters.

"The throughput right now is so far behind and has such a backlog that it'll take them several years to refit, refurbish, and repair the F-18s that are in unserviceable condition," Venable told the Washington Free Beacon. "They can't catch up even if the Trump administration gave them all the money they need."

Naval and Air Force pilots have been unable to train adequately due to a shortage of operable aircraft in both services, impacting readiness levels and depriving the military of pilots who are unable to log needed flight hours.

With five months left in fiscal year 2017 and a readiness deficit across all four military branches, Sen. Tom Cotton (R., Ark.) has advocated an emergency $26 billion supplemental spending bill that would direct some of the funds to readiness training for pilots.

Cotton, a member of the Senate Armed Services Committee, said Monday the funding has become necessary after eight years of defense cuts under former President Barack Obama.

"Trying to cut our defense spending to get a peace dividend as we did in the 1990s or to pay off domestic constituencies as Obama did is a self-defeating effort," Cotton said during a panel at the American Enterprise Institute in Washington, D.C.

"Your enemies get wind of what's going on, their aggression becomes vulgar, and you have to pay more to rebuild the capabilities and capacity that you lost just to get back to where you were," he continued.

Cotton said Congress needs to increase the defense budget by at least 15 percent in fiscal year 2018 to recoup the military’s losses.

"To put it briefly, we need more ships, more soldiers, more Marines, and more aircraft of virtually every kind," Cotton said. "More broadly, we need to invest in the men and women of our armed forces. We need to give them the training and equipment they need to do their jobs and we need to do this urgently."

The House and Senate Armed Services Committees will hold hearings this week on the military's readiness levels ahead of next month's National Defense Authorization Act negotiations.