Sen. William L. Scott, the controversial Virginia Republican whose overseas travels have stirred criticism in the state, returned to Latin America yesterday for his second multination tour of the region in 36 days.

Scott, who is not seeking re-election next year, was one of two senators to show up at Andrews Air Force Base for what was once planned as a 14-day, government-paid trip for 12 senators and their wives to Colombia, Argentina, Peru, Brazil and Panama.

A Scott aide said yesterday the senator decided to return to the region "essentially to get answers to further questions" left unanswered by his 10-day, three-nation trip last month.

Sen. Ernest F. Hollings (D-S.C.) was the only other senator who left with Scott in an Air Force jet that normally seats about 100 passengers. Senate Majority Leader Rober C. Byrd (D-W. Va.) picked Hollings to head the trip because of his role as chairman of a subcommittee that oversees the State Department's budget, Hollings aides said. Several Senate aides and three Army escorts, including a physician, also went on the trip.

Other senators invited for the trip either declined invitations or backed out for various reasons, according to a spokeswoman for Hollings' Washington office. Sen. Adlai E. Stevenson (D-Ill.), who once planned to make the trip, dropped it because he "had better things to occupy his time," a Stevenson spokesman said.

Details about the expected costs of the trip were difficult to obtain yesterday because the Senate officer who handled the travel arrangements went along and because the military's congressional liaison office was swamped with plans for numerous overseas travel requests during the current congressional recess. "They got so many trips going today, they are confused," said one Air Force officer, begging off a request for more details.

The trip, which will take Scott back to two of the same countries he visited last month, is one of numerous congressional "study missions" that House and Senate members are taking during the August recess. A recent survey by United Press International showed that more than 60 members of Congress are traveling to 39 countries and Alaska and Hawaii during the break.

The Senate has provided a $45,000 appropriation to cover the Scott-Hollings trip and an Army officer is taking $8,000 along from a Defense Department account to cover incidental expenses, an Army official said yesterday.

Scott has visited 34 countries during the past four years, prompting one major Virginia newspaper to describe him after last month's trip, as "a candidate for junketeer of the year."

"It may be an open question whether it is better to get Mr. Scott out of the country or keep him in the Senate," said an editorial in Norfolk's Virginian-Pilot. Citing New Times magazine story that once described Scott as the "dumbest" member of the Senate, the editorial added. "But the frequency of travel would seem to prove one thing: those who called him the 'dumbest' on Capitol Hill were wrong."

Scott repeatedly has defended his overseas trips as worthwhile. "I learned a lot about the canal . . . saw ships going both ways . . .," he commented after his previous Latin American trip that he said focused on the Panama Canal.

"That was a Defense Department tirp and this is a State Department trip." Scott administrative aide Jack White said yesterday. "This one will have a different emphasis."

Both Scott and Hollings aides said the senators will face a busy schedule on the trip, which is scheduled to end Aug. 27 with a meeting with the Panamanian leader, Gen. Omar Torrijos. During Scott's earlier visit, many of panama's top foreign ministry officials failed to show up for a dinner meeting with him and he had to cancel a trip to Brazil when that country's leaders told the U.S. Embassy they would not be available to see Scott on a weekend when he was scheduled to be there.

The 14-day trip began with the senators' arrival in Bogota, Colombia, at mid-day yesterday. Scott reimbursed the government $1,285 for his wife Inez' air travel last month and White said he was confident Scott would pay for her airfare again this trip "if it's proper." Hollings' staff said it did not know who would pay Mrs. Hollings' costs.

Despite the critical newspaper comments about Scott's last trip, White said Scott also received "compliments from many colleagues" in the Senate after he reported on the trip Aug. 5 in a Senate speech. In his remarks, Scott reaffirmed his strong opposition to the Carter administration's proposed revision of the Panama Canal Treaty and questioned whether the Panamanians would have "the necessary skills or expertise to operate the canal . . ."

White said Scott will prepare a second report after this trip, which was approved by the Senate on July 15 at the urging of Byrd. The funding resolution, which was approved without debate, called for up to 12 senators picked by Byrd and Senate Minority Leader Howard Baker (R-Tenn.) to visit South America "to conduct a study on United States economic and security interests."

Although the Senate action came five days after Scott had returned from the area on a trip arranged by the Armed Services Committee, Byrd then said. "I am convinced that such a study is long overdue and that now is the time to do it."

Baker's office could not be reached yesterday for comment on why Scott was chosen for the latest trip. Nor could aides to two Democrats, Sens. Lloyd M. Bentsen of Texas and Howard W. Cannon of Nevada, explain why those two backed out of the trip before being listed as members of the delegation.

Asked if possible adverse publicity about congressional travel overseas figured in Stevenson's decision to remain in Washington.Harold R. Levy, a Stevenson aide, said, "I think everybody's aware of that." Stevenson had planned to do some intelligence subcommittee work "on his own" during the trip to help justify his time in South America, Levy said.

In its congressional travel survey, UPI found 49 House members and 15 senators planning trips outside the 48 contiguous states, but said the actual number traveling could be higher because committee aides were reluctant to discuss the trips.

Alaska is the most popular destination this summer, with 18 members of Congress going there to study national parks and one to study the new trans-Alaskan oil pipeline and fishing around the Alaska coast.

Problems under study include mail delivery to American military personnel stationed in Bahrain, which Rep. Edward J. Derwinski R-Ill, is looking at, and packaging of hazardous materials, which Rep. Bob Eckardt (D-Tex.) is planning to examine in Switzerland, according to UPI.