Campaigning aggressively against President Carter in five southern and eastern states, Ronald Reagan today accused his rival of ineptitude, vacillation and manipulating budget figures to conceal the size of the federal deficit.

"The conduct of the presidency under Mr. Carter has become a tragi-comedy of errors," Reagan declared at airport rallies here and in Texarkana, Ark.

"In place of competence, he has given us ineptitude," Reagan said, "Instead of steadiness, we have gotten vacillation. While America looks for confidence, he gives us fear. His multitude of promises so richly pledged in 1976 have fallen by the wayside in the shambles of this administration."

Despite the florid rhetoric, there was more of old style than of new substance in the Reagan campaign.

"From now on it's three yeards and a cloud of dust," said Reagan strategist Stu Spencer, using a football metaphor.

He was emphasizing the basic last-week strategy of the Reagan campaign, which is to focus on Carter's record and try not to say anything that might divert attention to Reagan instead. The Reagan campaign team believes that its candidate is ahead and the emphasis at every stop is on doing nothing that would blow the lead.

Today, campaign attention was focused away from Carter and on Reagan's own staff problem of the moment, the resignation of foreign policy adviser Richard V. Allen. But the belief among Reagan aides was that the Allen resignation would have little, if any, effect on the outcome of Tuesday's election. The atmosphere on Reagan's campaign plane, "LeaderShip 80," was so relaxed that chief aide Michael K. Deaver took time out from his duties for a round of bridge with reporters.

This morning, leaving his hotel in Dallas, Reagan was asked about a quote attributed to pollster Lou Harris, who said that Reagan had done well in the debate with Carter Tuesday and that the election was now his to lose.

"Well, I'll tell you that if Lou Harris says the election is mine to lose, the best thing for me to do is stop talking to you people," Reagan replied. "I'm only kidding," he added, with a grin.

Reagan supporters did some kidding of their own about Carter's statement in the debate that he had consulted with his 13-year-old daughter, Amy, about what the most important issue in the campaign is.

"She said she thought nuclear weaponry and the control of nuclear arms," Carter said, to the groans of some in the debate audience in Cleveland.

At a Reagan rally in the Southern Methodist University auditorium Wednesday night, two huge signs pushed Amy for secretary of state or secretary of defense. And when Reagan, in an earlier speech in Fort Worth, repeated a standard line about Carter acting as if someone else had been running the country the past four years, Reagan partisans chanted; "Amy, Amy."

Reagan spoke for 40 minutes at the SMU rally, interweaving so many of his basic speeches that the address could have been described as "The Collected Works of Ronald Reagan."

It was all by design, because the campaign is selecting the best 28 minutes of this performance for a half-hour commercial to be televised nationally Friday night.

The Reagan campaign has set aside $5 million for its final television campaign, which includes another half-hour speech on election eve.

In his speeches today in Arkansas, Louisiana, New Jersey and Pennsylvania, Reagan accused Carter of withholding federal budget figures until after the debate because he wanted to conceal the fact that the federal budget deficit is now $59 billion plus $14.2 billion in off-budget items.

Then, mocking Carter's pledge of four years ago, Reagan said: "No one should feel any obligation to reward his four years of total mismanagement with four more years to do the very same. He did not give us a government as good as the people, as he said he would do. He only gave us a government as good as Jimmy Carter, and that isnT good enough."

In a television interview Wednesday night in Dallas, Reagan was asked whether Carter would gain if Iran releases the American hostages before Election Day. Reagan replied that he thought most Americans would think that the hostage situation "has not been well handled [because] there was no need for them to be taken hostage in the first place."

Later tonight, at a working-class bar in Bayonne, N.J., Reagan used language he has rarely employed in a campaign. After assailing Carter's economic performance, he said ". . . and he's seeking reelection but I'm damned if we're going to let him get reelected."