President Reagan did not consult the Joint Chiefs of Staff before deciding to scrap the 7.6 percent October pay increase for the 2.1 million men and women in uniform, Gen. Charles Gabriel, the Air Force chief of staff, said yesterday.

Gabriel said that he and his fellow chiefs would be willing to trade weapons for pay raises if such a choice has to be made, but responded, "I'm not going to give you a hit list," when asked what weapons he would be willing to give up.

Gabriel, answering questions from Pentagon reporters over breakfast, said not only had he not been consulted about the pay freeze but also he had not been officially informed that the president had decided to impose it.

Later in the day the Pentagon's public affairs office issued a statement apparently designed to take the political sting out of Gabriel's remarks.

It said that Marine Corps Commandant Robert H. Barrow, acting chairman of the Joint Chiefs, "stated that the United States military establishment is ready to respond to the president's request and do its part in restoring economic strength to the nation."

Lt. Col. L.T. DeLorme, a deputy to Henry E. Catto Jr., assistant secretary of defense for public affairs, whose office issued the statement, said, "I don't know" when asked where Barrow had made the statement.

Catto's office paraphrased what it said were Barrow's remarks, without quoting him directly at any point or explaining where or why he made the remarks.

"He said that the relations between the Joint Chiefs and the White House have never been better," the public affairs office statement said of Barrow.

Reagan decided on Monday to freeze the basic pay of military personnel and government employes. White House spokesman Larry Speakes indicated yesterday that the president's decision had passed the point of no return.

"I think Defense Secretary Caspar W. Weinberger has spoken on behalf of his people over there, and I don't anticipate them coming in to see the president on this subject," Speakes said when asked about Reagan's failure to consult the Joint Chiefs.

"I'm sure Secretary Weinberger knows the views of the military and takes them into consideration," he said.

Another administration official who did not wish to be identified scoffed, "What was Weinberger supposed to do? Call up the chiefs and ask them if it was all right to go along with the president?"

Gabriel's remarks did not appear to be a counterattack on the president's freeze decision. The general addressed the question only when reporters questioned him.

"We had hoped the worst we would see would be a 4 percent cap" on military pay in fiscal 1984 if the projected 7.6 percent raise proved unattainable, Gabriel said. "We were not consulted. Options of trading programs was not given to us."

The chiefs say they fear that the all-volunteer force will lose its best and brightest people if military pay is not kept abreast of salaries paid by private industry for comparable jobs. They worry about recruiting and retention when jobs become more plentiful on the civilian market.

Asked if he thought the chiefs, as the nation's highest military body, should have been consulted directly before the president approved the pay freeze, Gabriel replied:

"I would have appreciated having a part in that decision, yes." He added that the chiefs have had a close working relationship "with the senior leadership".

"I don't know that this decision would have been any different if we had been consulted," he said.

Now that the decision apparently has been made, "we're going to be team players," Gabriel added.

In response to other questions, Gabriel said the United States has the "capability" to launch its missiles after sensors warned that Soviets missiles were on the way. He hinted that the Air Force had practiced launch-on-warning tactics in training exercises simulating nuclear war.

"It's a destabilizing situation if we have to do it," Gabriel said of launch on warning, but he stressed that military leaders had no more inclination to resort to that strategy today than they have had in the past.

U.S. policy is to hold its nuclear fire at least until Soviet warheads have landed.