Britain's bombing of Falkland Islands airfields today may represent an effort to crack the morale and determination of the Argentine troops on the islands to avoid the necessity of a full-scale assault that could be bloody, British analysts say.

While the raid constitutes a sharp escalation in military pressure on Argentina, it still leaves Britain a long way from its main military objective of recapturing the islands.

Most analysts maintain that a frontal attack on Port Stanley, the capital and chief population center of the Falklands, is at least three weeks away because key elements in the British naval task force are not yet in position around the islands. About 3,000 Marines and paratroopers and 20 Harrier vertical-takeoff warplanes are as much as two weeks' sailing time from the war theater.

Britain might go for "a bold stroke" by attacking the port in the next few days when the Argentines are not expecting it, said retired colonel Jonathan Alford, a military analyst with the authoritative International Institute for Strategic Studies.

But he said it was more likely that task force commander Rear Adm. Sandy Woodward, with approval of Prime Minister Margaret Thatcher, will "nibble away at the edges" and harass the Argentines by exercising some of the many lesser options at his disposal.

These could include landing troops on lightly defended West Falkland Island as a diversionary tactic, helicopter and Harrier attacks on Argentine positions, and commando raids on fuel and ammunition dumps, Alford said.

"If I were the commander, I would want to have some significant military event every 24 hours" to keep the Argentines guessing at what will happen next, Alford said.

The point is to steadily increase the pressure to demoralize the Argentine forces and encourage a surrender without assaulting Port Stanley. Most of the 6,000 to 10,000 Argentine troops on the islands are believed to be concentrated around the port, and a full-scale assault could be bloody and have major political repercussions here for Thatcher.

The task force must keep up its military momentum, Alford said, because it cannot maintain an aerial blockade for more than a couple of months. That's how long the carriers on which the Harriers are based can stay on duty in the stormy South Atlantic without returning to base for an overhaul, he said.

The cratering of the airport runways means, at least temporarily, that Argentina probably no longer can resupply the islands by air even if its planes can make it through the air and sea blockade that Britain imposed yesterday.

However, a Falkland Islander who came to Britain last week said the Argentine forces may be able to repair the runway at Port Stanley quickly. The Argentines brought in many steel plates to widen the runway after they invaded four weeks ago, said Peter Felton, and "I don't see any reason why there shouldn't be enough for a temporary airstrip."

Alford also said it would be relatively easy to repair the runway, and, while Britain could bomb it again, he said, "mending the runway is a lot cheaper for Argentina than bombing it is for Britain."

Disabling the airport also helps protect the British naval force that is enforcing the blockade. Any Argentine air attack on the task force would now have to be launched from the mainland or a distant aircraft carrier, which would allow Argentina's Mirage and Skyhawk fighters little combat time before having to return to base to refuel.

However, analysts believe Argentina had not stationed any significant part of its Air Force on the islands precisely because it expected an attack like today's.

The attack by the carrier-based Sea Harriers provides the first public evidence of just how close the task force is to the Falklands, because the jets only have a 150-mile combat radius when fully loaded. It is almost certain that the aircraft carriers and support ships are east of the Falklands to remain out of range of Argentina's planes.

The Argentines on the Falklands have the advantage of being 300 miles from home rather than 8,000 miles, like Britain's task force.

The use of the high-altitude Vulcan bomber is the first demonstration that Britain has put to use training maneuvers undertaken since the Argentine invasion. The aging delta-wing Vulcans were being retired from Britain's nuclear strike force, but they were converted to conventional bombers for the Falklands operation. The normally tight-lipped British Defense Ministry spokesman readily talked last week about crews dropping 1,000-pound bombs on training runs over a Scottish island.

Recent Marine training maneuvers likewise provide a good indication of eventual British tactics if Argentina does not crack. British correspondents aboard the Canberra, a cruise liner now converted into a troop carrier, have reported in censored dispatches that marines have been practicing seaborne assaults on British-owned Ascension Island in the mid-Atlantic, 3,500 miles north of the Falklands.

[United Press International, noting that one of Britain's weaknesses is its lack of long-range heavy transport aircraft, said the British may ask the United States to ferry supplies to their Ascension Island staging base.]