WITH U.S. TROOPS, SAUDI ARABIA, FEB. 11 -- On the first day of the Persian Gulf War, Air Force Col. Dave Sawyer flew his A-10 attack plane over the vast desertscape of Iraqi armor, bombed his targets almost effortlessly and thought, "This is gonna be pretty much a turkey shoot."

Then the clouds rolled over huge stretches of the target zones, obscuring much of the Iraqi army for more than six days, Sawyer recalled. When the clouds finally lifted on the seventh day, the tank-hunting pilots discovered a different military arrayed below them.

"He'd buried a whole army out there," said Sawyer, marveling at Iraqi President Saddam Hussein's quick action to hide his ground forces. "He was much harder to root out."

For the the past several weeks, Sawyer, a 48-year-old veteran of Vietnam bombing missions who commands the 23rd Tactical Fighter Wing, and other pilots have most frequently described their missions as "very frustrating," saying that first cloudy week gave the Iraqi military the jump it needed to fully brace for the aerial onslaught.

"There's an across-the-board frustration," said Col. Erwin C. "Sandy" Sharpe, 49, commander of the 354th Tactical Fighter Wing. "He's dug himself in, making it difficult to find a particular target. What you were looking for in Vietnam was hiding under the trees; here it's hiding under the sand."

"It's like trying to flush a buck out of a thicket," said Sawyer, a Wyoming native who attended the same high school as Defense Secretary Richard B. Cheney in Casper. "Now it's hunt and peck."

Each day, the pilots and their big, lumbering A-10 Thunderbolt IIs -- more widely known as "Warthogs" -- patrol the desert skies, attempting to distinguish clever decoys from real tanks, searching for Scud missile launchers or moving convoys. "When we're lucky we take out armor and tanks," said Sawyer, "On the other hand, anything you destroy decreases {Iraq's} ability to wage war."

Capt. Bob Ginnetti, 30, from Chantilly, Va., is a flying traffic cop for a group of Warthogs. His lightly armed observation craft, dubbed the OA-10, cruises the battlefield in search of targets. When he spots a suspect tank or convoy, he fires a white phosphorous, or "willie pete,"rocket to mark the target for his colleagues in the more heavily armed attack craft.

"I'm usually out there by myself looking for a target," said Ginnetti, a lanky man who followed his father into the Air Force and has flown about 20 missions since the war began. "One day a missile came flying by, the area was too hot, so I moved on."

Even though the pilots say the black marks, scorched armor and bomb craters are turning more and more areas of the desert into a moonscape, Ginnetti noted, "I'm surprised how much stuff is still out there."

For the pilots, these missions have become intensely personal.

"It's a fraternal organization that trusts each other with their lives," said Capt. Larry Merington, 36, an Air Force reservist who was running the marketing department of a Houston waste-management company until he was called to active duty six weeks ago. "I cover for my wingman. I don't want to have to go see his wife and say I didn't do my job right."

Still, when the pilots climb into the cockpit of the stubby A-10 and settle into the reinforced titanium tub designed to protect them from ground fire, they attempt to shove emotions aside.

"The time for apprehension and puking your guts out is before the mission," said Sawyer, who as a Vietnam vet has found himself counseling many colleagues among the new generation of pilots. "Once you're in the cockpit, you put it out of your mind. It takes a lot of concentration, you have to think about hitting the target. Now on the way back, that's sometimes when you start shaking."

The men and women who service the planes on the ground whisper that they get numerous requests to change the seat pads when pilots return from particularly tough missions.

And at night, lying in their heated tents, the pilots say their minds wander homeward in the quiet minutes before they drop off to sleep. Twenty-nine-year old Capt. Rich "Griff" Griffin, said he thinks often of his wife and baby boy, who will turn 3 in April, and what would happen to them if he did not return from a mission: "But you can't think about stuff like that when you fly."

Death is also a subject carefully sidestepped by the families of most of the men who are now on the front lines of the air war.

Merington has telephoned his family several times since the war began: "Bullets are firing at you on a daily basis, but nobody talks about that. Instead they ask, 'How's the weather?' and 'Are you getting enough to eat?' "

But, in much the same way, the pilots and the men and women who arm their airborne killing machines for hundreds of missions each week don't allow themselves to think of the Iraqi men who are dying alongside their entrenched tanks and inside truck convoys below.

"You can't walk around thinking, 'Boy this is really bad,' " said Staff Sgt. Timothy Neuman, 29, a weapons crew chief who said he has loaded more bombs here in a week than he usually loads at his home base in England in a year. "But it does go through your mind."

The aircraft he helps arm bristle with some of the most deadly weapons in the Air Force arsenal.

On the ground, sandwiched between sand-filled steel revetments, a smorgasbord of bombs and missiles awaits each plane. There are sleek, white Maverick missiles that burrow through a tank's shell and burst inside; fat, green cluster bombs that split open in midair and rain more than 200 "bomblets" on an area the size of a football field; and 500-pound Mark 82 gravity bombs that leave deep craters in the sand.

Beefy men with grimy hands pull the weapons off large pallets using small carts with automated arms and lift the bombs and missiles, then struggle with wrenches to clamp them beneath the wings and belly of the plane.

Other teams feed a belt loaded with 1,174 depleted-uranium shells into a gun that can spit out 70 of the projectiles a second, shredding anything in its path. The entire front end of the plane is constructed around the internal 30mm cannon; its rotating barrel juts out the nose of the plane.

One bomb-loading crew has pinned a cardboard sign above its arsenal of waiting missiles and bombs: "Do it for the POWs."

At another stop on the windy runways, returning planes line up at a refueling "hot pit," where they guzzle up to 10,700 pounds of jet fuel in preparation for their next mission.

A large plywood sign at the edge of one runway refueling outpost beckons: "Desert Storm One-Stop. You kill 'em. We fill 'em."

In the first four weeks of the air war, the A-10s -- long the stepchild of an Air Force enamored of its high-speed jet fighters -- have emerged as tough war heros. In fact, before the Persian Gulf War the Air Force had agreed to turn over most the A-10 force to the Army. But in the current battle plan, the Air Force -- against the wishes of the Army -- pushed the planes into battle far ahead of their intended mission, which is to protect U.S. troops in ground battle by blasting approaching enemy tanks and armor.

"The planners said, 'Don't go out and lose all the A-10s doing Air Force stuff,' " said Sawyer.

Because it is relatively slow and low-flying, the aircraft is not designed to fly patrols over enemy territory in search of stationary targets as they are now being used. But the virtual absence of an Iraqi air threat and its sporadic air defenses on the battlefield have allowed the A-10s to operate effectively even with their limitations. Only one of the aircraft has been downed by hostile fire.

Another plane limped back to its base last week after Iraqi missile or artillery fire ripped a gaping hole in its wing.

"Everything was sucked out of its wing," said Senior Airman Jennifer Earnshaw, 22, of Cumberland, R.I., who was a member of the aircraft battle-damage assessment team that inspected the crumpled and bullet-riddled wing. "Any other aircraft would not have made it back."

The performance of the planes has earned new respect for the pilots and the crews who maintain the Warthogs.

"I always got dogged out by other people," said Earnshaw. "They would say the A-10 is not even a jet -- it's just an ugly bird. Now everybody's opinion has changed."

Despite the hectic pace of bombing operations, most ground crew workers say they feel far removed from the fighting. Asked where they get most of their news, the bomb loaders, mechanics and other ground crew members respond quickly, "CNN."

But when the war moves into the ground phase and the A-10s assume their more traditional mission of flying cover for allied ground forces in battle, more frequent reminders of war are likely to be seen at the air bases.

During one ground battle, it was determined that an armor-piercing missile fired from an Air Force A-10 killed seven U.S. Marines inside an armored vehicle near the Kuwaiti-Saudi border on Jan. 29.

"Any time you put people with live weapons, there's always the possibility of mishap," said Lt. Gen Charles Horner, the senior Air Force officer in the gulf. "And it is very, very disturbing when it happens, and it's something we all take very seriously."

Just as pervasive is the fear of an aircraft being shot down by enemy fire. "If you worked on a plane even months ago, and it goes down," said Sgt. Daniel Wassum, 22, of Winston-Salem, N.C., "it tugs at your heartstrings."