Almost as soon as Defense Secretary Caspar W. Weinberger described the U.S. bombing raid at a news conference Monday night, analysts inside and outside the military began questioning the use of Air Force planes.

Why, it was asked, would the Pentagon choose to send Air Force F111s 2,800 miles from Britain to Libya, subjecting them to the risk of multiple midair refuelings, when two aircraft carriers with 170 warplanes steamed a few hundred miles from the targets? Did the Joint Chiefs of Staff approve a convoluted plan in order to give the Air Force a piece of the action or to demonstrate support for the raid by at least one ally?

The questions echoed criticism that followed the four-service invasion of Grenada in 1983, and the Pentagon was quick to deny improper motives.

"Absolutely untrue," Pentagon spokesman Robert B. Sims said. "It is unfair to those pilots to make that kind of representation."

Yet the debate continued during the week as some experts, especially in Navy blue, argued that the carriers could have done the damage with less risk to U.S. pilots. Others -- including Navy Secretary John F. Lehman Jr. -- said the joint operation made sense, tactically and politically.

In the U.S. arsenal, only the Air Force F111 and the Navy A6 can attack with precision at night, in any weather. Aboard the USS America and the USS Coral Sea, 18 A6 bombers were in shape to fly; the plan called for 32 bombers to attack, and 25 planes managed to reach the targets and drop their bombs.

There were alternatives, of course. All 18 A6s could have been used, and fewer targets attacked; even then, though, none would have been held in reserve, in case a second attack was ordered. The A6s could have attacked in two waves or staggered the raid to cover two nights; but the second attack could have been far riskier than the first.

The Navy could have flown extra A6s from Norfolk to the carriers, removing submarine-hunting planes to make room; some Navy officers said such an operation would have been no more complicated than flying the Air Force refueling planes to Britain over the weekend. But others said the logistics would have been complex and the operation likely to be detected.

The Navy could have used F18 Hornets as well as A6s, since the Hornets were designed to be attack planes as well as fighters. But because the F18s lack the special A6 ground-avoiding radar, they would have had to fly in at a higher altitude, enhancing the risk of being shot down.

To subject its pilots to even less risk, the Navy could have sent a battleship from Norfolk to attack with naval gunfire. But that, too, would have taken longer and jeopardized the element of surprise.

In addition to the military arguments, Lehman offered two political justifications for the joint operation in a speech last week. It was useful, he said, to see which allies would come through, "and the U.K. came through like gang-busters."

And it was useful, Lehman added, to show Libyan leader Muammar Qaddafi that even if there are no American carriers in the Mediterranean, his country is not beyond the reach of U.S. force.

By week's end, however, some officers argued that such a demonstration may have backfired. With Prime Minister Margaret Thatcher under attack at home and few other allies supporting the raid, they said, Qaddafi might assume that the United States would be reluctant to attempt a similar maneuver soon.

Inside the Pentagon, Air Force officers certainly seemed pleased after completing their first bombing mission since Vietnam. But no evidence has emerged to suggest that such emotions played a part in devising the plan.