CRISIS IN THE BALKANS : Loss of Pilot Casts Pall on U.S. Air Base : Military: Comrades await word at facility that represents a slice of Americana in Italy.

The churches are well attended on a soft spring day, and so is the golf course. Cyclists race along country roads. Hamburgers sizzle. And two deadly-looking FA-18 fighters claw into the sky.

It is a workaday Sunday in what may be the only American small town where tortured Bosnia-Herzegovina is a real place, a palpable threat, a source of grief.

On Friday, a missile fired by Bosnian Serbs downed a U.S. F-16, the first plane from this base to be lost in the Balkan fighting. There was still no word on the fate of the pilot Sunday, but his loss hung in the air at a base peering as resolutely east as it did when the threat came from communism.

The 4,300 Americans who operate Aviano Air Base in northern Italy are the cutting edge of North Atlantic Treaty Organization patrols over Bosnia. It is across the Adriatic Sea, a quick hop to danger.

“On a clear day, you can see the coast from the control tower. We’re flying over central Bosnia 30 minutes from takeoff,” said Col. Richard L. Brenner, vice commander of the U.S. Air Force 31st Fighter Wing, here in a piece of Italy as American as Storm Lake, Iowa--Brenner’s hometown.

Warplanes from Aviano have flown over Bosnia nearly 20,000 times in the two years since the United Nations ordered enforcement of a “no-fly” zone and authorized air strikes to support the U.N. Protection Force there.

No one here talks about the missing pilot to strangers. Not even his name. Orders. His buddies from the 555th (Triple Nickel) and the 510th (Five ‘n’ Dime) fighter squadrons hope and wait and fly in his shadow every day to an alien land from a place like home.

“This used to be Sleepy Hollow. Now it’s like any fighter base in the States--the difference is that here the missions are real,” said Capt. Tracy O’Grady, a public affairs officer from Dayton, Ohio.

In the lee of the Alps about an hour’s drive north of Venice, Aviano has been home to U.S. combat aircraft for four decades.

It participated in the Cold War without firing a shot but has mounted half a dozen combat missions in Bosnia since February, 1994. Aviano pilots shot down four Serbian planes then and have struck Bosnian Serb ground targets since.

In addition to 42 planes from the two “Small Change” fighter squadrons, Aviano hosts Air Force F-15 fighters and A-10 ground attack aircraft, Navy EF-111A electronic warfare aircraft, and FA-18 fighters flown by the U.S. Marine Corps and the Spanish air force. Aviano also hosts U.S. Army helicopters and AWACS airborne warning planes on NATO assignment from Britain’s Royal Air Force, Brenner said.

There are now about 4,300 personnel at Aviano in a setting as familiar as Main Street. There is a high school with a championship volleyball team, a movie house, a bowling alley, a golf course, baseball and football fields, markets, a post office, a bank, Girl Scouts, Little League, police in Chevy Caprices--and a Burger King.

“You could pick this place up and put it any place in the United States,” said Senior Airman Dan D. Neely from Pensacola, Fla.

Coexistence is the name of the game. In the town of Aviano, where many of the signs are in English, the American Baptist Church lives companionably around the corner from the headquarters of what used to be the Italian Communist Party.

Federica Giavon from nearby Pordenone came to the base Sunday to watch takeoffs and landings.

As two Spanish FA-18s thundered away, she was told they were heading for Bosnia. “I hope they are careful,” she said.