WASHINGTON (AP) - The U.S. military, stretched thin following a post-Cold War downsizing, is feeling the pinch. Because of dual defense needs in Kosovo and Iraq, no aircraft carrier is cruising the Pacific. Instead, Air Force planes there have gone on alert for any trouble.

The gap in carrier coverage for the Pacific could last until the fall, when the USS Constellation is to arrive, defense officials said.

The USS Kitty Hawk, which was in the Pacific, was ordered to the Persian Gulf April 3 to free up the USS Theodore Roosevelt to join the NATO airstrikes on Yugoslavia. The Roosevelt arrived in the Adriatic Sea April 5.

Now, the Pentagon again is scrambling U.S. military assets around the globe to meet a NATO request for 300 more U.S. warplanes for Kosovo. That could mean adding a second carrier, sending the USS Enterprise and its 75 aircraft - which just completed a six-month Gulf deployment, U.S. defense officials said. More warplanes could come from forces around Iraq and Korea.

A senior defense official, describing the search for resources, said the U.S. military's ''elasticity'' has been reduced since the Cold War, when the Navy had 600 ships, for example, compared with 324 today. The official spoke on condition of anonymity.

In 1991, the Navy had 15 aircraft carriers plus one reserve, which is just enough to keep one each in the three places the Pentagon would like to protect 365 days a year - the Gulf, the Mediterranean and the Pacific.

Maj. Gen. Charles Wald, a strategic planner for the Joint Chiefs of Staff, acknowledged that as NATO's Kosovo air campaign continues, ''Over time, it will take a little bit of a toll.'' But he said the shifting of carriers and aircraft demonstrates the flexibility of today's leaner military.

As Congress considers a $6 billion White House request to pay for NATO military and humanitarian actions, House Speaker Dennis Hastert, R-Ill., said the Kosovo crisis has shown, ''Our troops are stretched too thin and our defense capabilities are now grossly inadequate.''

Leaving the Pacific unguarded by a carrier for long could send the wrong signal to North Korea, China or Indonesia. A visible U.S. military presence helps maintain stability, he said.

U.S. military doctrine calls for the Pentagon to be prepared to fight two regional wars at the same time. Defense officials insist that's still possible, even with the U.S. armed forces trimmed to 2.4 million active duty and reserves compared with 3.8 million in 1989.