The airmen, all based at Keesler Air Force Base, would begin flying home over the next two weeks, Air Force Captain David Small, spokesman for US Central Command Air Forces in Qatar, said on Saturday.
The group includes airmen who were scheduled to rotate home in September and others whose deployments would be cut short.
"Those who weren't scheduled to go home, we're going to send them home anyway to take care of their families and the hurricane damage," Small said.
Keesler, just off the beach in the Gulf Coast city of Biloxi, suffered a direct hit from Hurricane Katrina.
The storm wiped out much of its housing and other infrastructure. Small said most personnel and families on the base had been moved to temporary shelters.
"Everything was under water," he said. Small said he had heard no reports of storm-related deaths on the base.
Keesler houses both active duty airmen and Air Force Reservists.
The decision to send Keesler-based airmen home was made by top Air Force officials with the support of Brigadier-General Allen Peck, the deputy commander of coalition air forces in the Iraq and Afghanistan theatres.
Peck is based at al-Udaid Air Base in Qatar.
Small said the 300 airmen will be leaving many bases in Iraq and Afghanistan as well as surrounding countries in Central Asia and Arab states of the Persian Gulf.
Some will be flying home on commercial airlines, he said.
He added the Air Force would ensure the early departure would not damage the Air Force's fighting capabilities, which include ground attack sorties, cargo and fuel deliveries, air-to-air refuelling and troop transport.
"We're making sure the unit commanders here can still conduct their missions without the folks from Keesler. There are about 18,000 airmen in the theatre, so we can pick up the slack"
David Small, spokesman,
US Central Command Air Forces in Qatar
"We're making sure the unit commanders here can still conduct their missions without the folks from Keesler," Small said. "There are about 18,000 airmen in the theatre, so we can pick up the slack."
A statement on Keesler's website described damage to the base as "severe enough that we are unable to leave our shelters until Thursday at the earliest".
Base residents are waiting for recovery teams to clear debris and repair damage before Keesler is reopened.
Air Force personnel serve shorter, more frequent deployments in the war theatres than do army and marine forces.
Air Force deployments
Air Force deployments average about four months - but can extend to a year, Small said.
By contrast, army deployments last from 10 months to a year, and marines are sent for about seven months.
Keesler houses the US Department of Defence's weather school, the Air Force's second-largest medical facility, and handles training in hi-tech command-and-control and computer networking.
US military officials have said there are no plans for a large-scale shifting of US troops from Afghanistan or Iraq to assist recovery efforts.
The commander of a Louisiana National Guard brigade based in Baghdad had asked that his 3700 soldiers be sent home a few weeks early to deal with the crisis.
Lieutenant-General John Vines, commander of Multi-National Corps-Iraq, said on Friday that US troops in Iraq whose family members were injured or killed by the hurricane may be allowed to go home.
Those who have no confirmed casualties among family members will have to stay in Iraq, he said.
Vines said that to allow soldiers from Mississippi and Louisiana to return home early would put their fellow soldiers in Iraq at greater risk.