The majority of the House defense appropriations subcommittee is expected to vote today to bust President Carter's military budget by adding a $2.4 billion nuclear aircraft carrier to it.

But Rep. Joseph P. Addabbo (D-N.Y.) who is slated to succeed the retiring Rep. George H. Mahton (D-Tex.) as defense subcommittee chairman, said last night that such a vote will not settle the issue.

Rather, said Addabbo, he and his allies will continue to fight against building another Nimitz nuclear carrier by recommending next year that it be canceled as a luxury the nation neither needs nor can afford.

Carter did not request any money for a few aircraft carrier in the defense budget he submitted to Congress in January. But, to the distress of Addabbo and his allies, the administration switched its course last month and said it would accept a conventionally powered carrier if it were added to Carter's budget.

"I don't know what to say they were thinking when they did that," complained Chairman Robert N. Giaimo (R-Conn.) of the House Budget Committee in an interview yesterday. He said the administration's turnabout just made it easier for pro-carrier forcus in Congress to argue that if a new carrier is to be built it might as well be the best one - a nuclear powered Nimitz.

"It's just a terrible waste of defense money," said Giamo of the $2.4 billion Nimitz. "It doesn't contribute to national defense vis-a-vis the Russians," he continued, adding it will be vulnerable to sophisticated Soviet weapons.

House opponents of the nuclear carrier, while predicting the ship will be approved today by the subcommittee, said there is a good chance the subcommittee will vote against $1.1 billion nuclear cruiser the House Armed Services Committee added to the Carter defense budget.

Although funding the nuclear carrier would push Carter's defense budget above his $126 billion request, House strategists believe they can keep from breaking through Congress' target ceiling of $128.7 billion for national defense, with $126.3 billion of that for the Pentagon and most of the remainder for nuclear warheads built by the Energy Department.

THowever, to fit the defense budget under Congress' ceiling the House defense appropriations subcommittee must deep cuts in other parts of Carter's budget. This cutting is already being done within the subcommittee, members said yesterday.