President Reagan defended his firing of the striking air traffic controllers before a courteous audience of union carpenters here today and predicted that his economic program would bring about an "American renaissance."

Marking the end of his month-long California vacation with an appearance at the centennial celebration of the United Brotherhood of Carpenters and Joiners of America, Reagan spoke glowingly of the promise of his economic program.

"The foundation has been laid for an American renaissance which will astound the world," he told the union audience, "a new era of good feeling in America, a time when jobs will be plentiful and the richness of the country can be shared by anyone who is willing to work."

Reagan's advance text did not mention the Professional Air Traffic Controllers Organization (PATCO) by name, but before the 2,600 union delegates he did, as he argued again that government workers have no right to strike.

"You are the employers of all who serve in government," he told his audience. "None of us in government can strike against you, and the interest of you, the sovereign people."

Immediately after Reagan left the convention hall, carpenters union President William Konyha distributed a statement defending the right of government workers to strike.

Reagan was followed on the podium by Democratic National Chairman Charles Manatt, who called the administration "a wrecking crew" and said it was "the most anti-union, anti-labor administration in Washington since Calvin Coolidge." At that point, the delegates erupted with applause.

Reagan had been met by pickets when he arrived in Chicago Wednesday night, and his aides were prepared for a mixed reaction by the delegates. But his reception in the hall today was friendly, and he was interrupted frequently by applause.

Several delegates said after the speech, however, that the president's reception was due more to respect for the office of the presidency than his stance on the PATCO strike.

"I hate to see any union broken," said M. H. Tipton of Shreveport, La. "That's what they're doing, putting PATCO out of business. Whether I agree with PATCO, I don't like to see them done away with."

In his speech, Reagan pledged support for the collective bargaining process and promised an open door to organized labor in his administration, something the leaders of various unions say has been lacking so far in his presidency.

Reagan also made a partisan appeal for union support, which was instrumental to his election last November, when he said to applause that "Organized labor should not become the handmaiden of any one political power."

But most of the president's speech dealt with his economic program. While he claimed that his administration had "gotten control" of government spending, he pledged a continued attack on the federal budget.

"The war for a healthier economy is not over," he said. "The struggle for more jobs and less inflation will continue to be the focus of this administration in the months ahead."

Reagan promised more budget cuts to reduce inflation, and said that when inflation is brought under control "Interest rates will come down. And when they do, they will stay down."

He also supported the Federal Reserve Board for "following a conservative and careful approach to the money supply which will ensure that once recovery begins it won't kick off another round of inflation."

Manatt, in a speech kicking off a new round of criticism, bitterly attacked Reagan's economic program. On Social Security, he said, "The Republican Party is a friend of Social Security the way Colonel Sanders was a friend of chickens."

He charged that the Reagan administration is one "of privilege and profit, that chooses the haves over the have-nots, the rich over the middle class, the powerful over the vulnerable."

And on the PATCO strike, he said, "The president of the United States ought to be a bigger individual than to praise Polish workers for striking against their government and then jail American workers for doing the same thing."

After the speech, Reagan returned to Washington, where he will begin final deliberations on reductions in projected defense spending levels for fiscal 1983 and 1984.

On Wednesday night in Chicago, Reagan, noting that The Washington Post had suggested that he was retreating on his defense goals, pledged that any reductions in defense spending will not come at the expense of his promise to boost the Pentagon budget by an average of 7 percent a year.