President Reagan, one day after the first military clash during his administration, told a cheering Navy crew today that friends and foes should know "America has the muscle to back up its words."

Reagan, whose aides chose not to awaken him for six hours after U.S. jets shot down two Libyan warplanes early Wednesday morning, told the crew of the aircraft carrier Constellation that "we all sleep a little bit better at night knowing that you are on duty."

The president watched F14 Tomcats, identical to the planes that shot down the Libyan jets, take part in a show of carrier aviation strength, and he briefly took the helm of the 84,000-ton Constellation during a day in which he celebrated America's military.

"This ship represents a powerful force in an uncertain world," Reagan said.

The president drew one of the loudest of many cheers he received when he referred to the aerial battle over the Mediterranean, and he denied that the United States had sought a fight.

"We didn't go there to shoot down a couple of Libyan planes. They came out and fired on ours," Reagan said.

Reagan said his administration had determined not to recognize what he termed the "artificial line" -- Libya's 1973 claim that its national waters extend about 200 miles north of the southernmost tip of the Gulf of Sidra over which the dogfight took place. The gulf cuts from the Mediterranean Sea into the Libyan shore for about the center third of the country.

"This foray by the Libyans was nothing new. Over the last couple of years, they have frequently harassed our aircraft out beyond that line in the Mediterranean . . . . We decided it was time to recognize what are the international waters and behave accordingly," the president said.

Reagan denied that had been a challenge to Libya. "We responded as we will respond anywhere. When any of our forces are attacked, they are going to defend themselves," he said.

Reagan told a Republican fund-raising party in Orange County tonight that he had been aware there might be harassment of the training exercise and that in such case there was only answer: "If our men are fired on, our men are going to shoot back."

On the Constellation, he also defended the decision by his top aide, counselor Edwin Meese III, not to wake him when the battle was first reported. "There was no decision to be made, or they would have awakened me," Reagan said.

He drew laughter at the $500-a-plate GOP party, saying, "If our planes were shot down, yes, they'd wake me up right away. If the other fellow's were shot down, why wake me up?"

Reagan and Meese sat in white, cloth-covered armchairs on the Constellation's flight deck to watch F14, A7E and A6E jets stage displays of bombing and aerial acrobatics over the Pacific 65 miles west of Los Angeles.

Reagan grinned and shielded his eyes from the sun as he watched a low-flying F14 break through the sound barrier close to the carrier, sending shock waves across the flight deck.

This was Reagan's first visit to the troops as president, and he cited his pride in America's fighting forces.

"While there may be some people who think that the uniform is associated with violence, you are the peacemakers. It's because of what you're doing that we can be sure of peace. So again, thank you for giving me this opportunity to greet you and tell you how proud we are," Reagan said.

"I know there have been times when the military has been taken for granted. It won't happen in this administration," he said to loud cheers.

Reagan said it was "earth-shattering" for a former cavalryman like himself to pay a first visit to an aircraft carrier.

"Let friend and foe alike know America has the muscle to back up its words and ships like this and men like you are that muscle," Reagan said.

He reiterated his commitments to a 600-ship Navy and to ensuring that military pay is "fair."

The Constellation had six days' notice of Reagan's visit, and the crew spent much of the time cleaning and painting, several crewmen said, adding that their officers told them it was important that the Constellation look good on television during the visit.

Decking in some passageways was covered to keep it spotless until minutes before the president walked on it.

The crew greeted Reagan enthusiastically and cheered when Capt. Dennis M. Brooks said they were proud of their president.

F14 pilots taking part in the air show here told reporters they envy their fellow Navy pilots who shot down the Libyan jets. "That's what we train for," one said.

Reagan was asked as he sat in the captain's chair on the navigation bridge how he would like to fly an F14.

"I think it would be a kick," replied the president, who last appeared with the Navy as a submarine skipper in the 1957 film "Hellcats of the Navy."