Two top Carter aides with no responsibilities in the area of foreign affairs accepted the hospitality of the government of Oman in June for a trip that included stops in Lisbon, London, the Middle East, with one going on to the Bahamas.

On June 3, a Boeing 707 jet sent by Oman picked up White House aide Thomas V. Beard and his boss, Sarah Weddington, in Lisbon and flew them to the Omani capital of Muscat for a two-day stay. The Omani government does not own a 707 and reportedly leases them from a Swiss company at a cost of $8,000 per hour.

A Boeing 707, on June 6, flew the pair to London, where they were the personal guest of one of the sultan of Oman's key British advisers, Brig. Timothy Landon.

The two then went their separate ways. Beard told The Washington Post this week that he flew from London on a $1,000 commerical airline ticket prepaid by the Omanis to join his family for a vacation in the Bahamas.

Weddington flew from London back to Lisbon, where she says she made connection to the United States via a presidential advance plane that was already in Europe making preparations for the Vienna summit.

Weddington told a reporter that she doesn't "remember" if the Omanis paid for her London-to-Lisbon plane ticket or not, although she said she doesn't "recall paying for it personally."

Both weddington and Beard defended their trip on the grounds that it was in the interest of the United States to foster good relations with the Omani government. Weddington said that she had been chosen to go because of her "agricultural expertise."

Beard defended the London leg of the trip, saying that the Boeing 707 "was going anyway" to deliver Landon and Foreign Minister Qais Zawawi. But sources knowledgeable about Omani government travel to and from England said that there is a daily Muscatto-London shuttle flight on which officials fly on a space-available basis. This plane is not a 707, but "an old tri-motor English plane," one source said. Qais Zawawi on other trips usually flies commerical, sources say.

Beard, in a series of interviews this week with The Washington Post, said that he had been told by White House attorneys before he left that the trip did not violate the Foreign Gifts and Decorations Act as long as it is deemed "to be consistent with U.S. interests."

Two National Security Council staffers, Robert Hunter and Gary Sick, sent a memo to White House Lawyer Patrick Apodaca on the day that Weddington and Beard departed stating that the NCS "concurs" in the visit and believes it "to be in the interest of the United States in fostering good relations with the Sultanate of Oman."

Beard, who was first asked about the trip to Oman by The Washington Post in early July, said last week that he had sent a check for $136 to Brig. Landon " a couple of weeks" after returning to Washington. The purpose of the check, Beard said, was to reimburse the Omanis for the "difference between the cost of my plane ticket from London to Nassau as opposed to what it would have cost them if I had come straight back to Washington instead of joining my family on vacation."

The amount of $136, Beard said, represented what he believed to be the cost of a ticket from Washington to Nassau.

"But just for fun, let's check it," Beard said to a reporter who was sitting in his office. He first dialed Delta Airlines, only to be told they don't fy to Nassau or London, and was referred to British Airways.

After a number of phone conversations with ticket agents and a lot of figuring on paper, Beard discovered that he had "shortchanged" the Omani government by $148.

Brig. Landon has not yet cashed his original $136 check, Beard said. "You know, he may not. He may just send it back to me. It'sd perfectly legal, as I understand it from the White House Lawyers, for the Omanis to pay all my expenses, portal to portal.

"I was just trying to be a good guy paying the $136 in the first place," he added.

Weddington is a presidential assistant whose area of responsibilities is women's affairs and domestic politics.

Beard, who works for her, is a buddy of White House chief of staff Hamilton Jordan and a little-known member of the "Georgia Mafia." Ordinarily, the closest Beard ever gets to foreign affairs matters is deciding which Americans will attend the funerals of heads of state, an assignment he was carrying out this week in Washington in connection with the services for Botswana's late President Khama.

Nevertheless, Beard has been an invaluable contact in the White House over the past two years for Foreign Minister Zawawi. They were introduced in February 1979, beard says, by Joel B. Paris III, who was Jimmy Carter's controversial National Guard director in Georgia.

Paris is now a lobbyist who clients have included Northrop and the British Aerospace Dynamics Group which is owned by the British government.

An intelligence source who is aware of Paris' activities in Oman says that his name is now circulating among American corporations as "the man to see" for anyone hoping to do business there.

In April of this year, The Atlanta Constitution reported that Paris was escorting top Omani Officials, including Qais Zawawi, through the Gulf-stream headquarters in Savannah, Ga., on a prospective buying trip.

Zawawi had just come from Washington where he had conferred with President Carter, a meeting which he had been unable to arrange during a prior visit in February 1979.

According to Beard, he received a telephone call from Paris on that first visit, asking him to have lunch with Zawawi and his entourage "because they wouldn't be seeing anybody else at the White House or the State Department and very much wanted to."

Beard took them to lunch at the White House mess, Beard said, and arranged for Zawawi to meet Ham Jordan and presidential adviser Robert Strauss that afternoon.

Calls to the Justice Department indicated that Paris is not registered as a foreign agent for Oman.

Beard, however, said that in the past Paris has called him "every three months or so to say he wants to stop by the White House to talk about Oman." m

When Zawawi returned to Washington this year, Beard said, Paris brought him to the hospital to visit Beard, who was recuperating from a skiing accident.

Zawawi had originally invited Beard and Ham Jordan to Oman in June, Beard said. When Jordan couldn't go, he suggested to Beard that Weddington might like to go in his place, Beard said.

Beard and weddington flew to Lisbon on the same presidential advance plane that later brought Weddington home.

A member of Qais Zawawi's staff brought the chartered 707 to fetch them. In Oman, they were personal guests of the foreign minister at his home. He hosted a luncheon for them and arranged an audience with the sultan. h

That night, Beard and Weddington were guests of honor at a dinner at the home of Zawawi's brother, Dr. Omar Zawawi, a businessman with worldwide interests.

"I never heard of Dr. Omar Zawawi until that night," Beard said. "No business was discussed."

Beard said that he expects to be seeing more of the Omanis. He has invited Brig. Landon to join him for geese hunting on the Eastern Shore later this year. Also, the Omanis have invited him and Weddington back to celebrate Oman's National Day on Nov. 25.