Michael F. Papa, a 25-year-old employe of Trans World Airlines at National Airport, was fatally stabbed in an airport restroom yesterday in an apparent robbery attempt near the TWA ticket counter where he worked as agent-in-charge.

Airport police took an 18-year-old Fort Belvoir soldier into custody moments after a TWA customer service agent stopped him as he tried to leave the restroom in the main terminal building.

Law enforcement authorities, said TWA service agent Tom Payne, alerted about a fight by an unidentified passenger, rushed to the restroom to find a stocky man in a plaid shirt "with blood on his shirt, trousers and sneakers" coming out the door.

After ordering the man to stay put, Payne found Papa inside the restroom "standing in a crouched position, clutching his chest, and bleeding profusely," said Al Hein, a special agent with the FBI's Alexandria field office.

Hein said the suspect was carrying a bloody hunting knife with a five-inch, fixed blade. The area where the attack occurred was almost empty of passengers at the time.

Police identified the suspect as Pvt. Joseph Patrick Shay of the 11th Engineer Battalion's 902nd Engineer Company at Fort Belvoir, a former resident of El Paso, Tex. Shay was arraigned at U.S. Magistrate's Court in Alexandria yesterday afternoon and ordered held without bond on a charge of first-degree murder.

Both Shay, who suffered a hand wound, and Papa were rushed to National Orthopedic Hospital in nearby Arlington. But Papa, with six stab wounds in the abdomen and chest, never regained consciousness, a hospital spokesman said.Papa was pronounced dead at 12:25 p.m.

Shay was described yesterday by Hein as a Georgia native who had lived in El Paso for the last five years. Shay completed high school there and subsequently worked in a cabinet factory, joining the army last July after he was laid off from his job, Hein said.

Maj. James E. Kiley, Fort Belvoir's public affairs officer, said Shay completed advanced individual training at Fort Leonard Wood in Missouri and was assigned to Fort Belvoir last Saturday. Kiley said he had no idea why Shay was at National Airport yesterday.

Papa was described by close friends yesterday as a devoted family man who seldom went out at night, reported to work at 5 a.m. every day and regularly arrived back at his Arlington home at 2:30 p.m. "He was a home type. It's a real shock to everyone here. His was a devoted and well-liked family," said neighbor Joseph Nowland.

Angus McClure, a New York-based TWA spokesman, said Papa worked his entire career at TWA'S National Airport facility, starting out as a ramp serviceman. He had been agent-in-charge of the ticket counter for the past seven years.

TWA field manager Ronald Schee said, "He was a fine individual . . . just a wonderful person."

Papa is survived by his wife Marie, and two sons, Gary, 17, and Michael, 20.

Hein said a preliminary hearing for Shay will be held in the U.S. Magistrate's Court in Alexandria at 3 p.m. on Nov. 26.