For some in Congress, 1980 has been a year of setbacks.

First, there was the FBI's Abscam operation involving allegations that eight members of Congress took bribes. Then there was the Nov. 4 election, in which 13 senators and 31 House members lost their bids for reelection. Congress also failed to agree on a $10,000 pay raise.

Now, it appears one of the most time-honored traditions of all, the junket, has been cut back.

In past years, after Congress has adjourned for the Christmas holiday, as many as a third of the members traveled overseas at taxpayers' expense.

This year, for a combination of reasons, foreign travel appears to have been restricted considerably.

Of course, some trips still are on. Rep. Bud Shuster (R-Pa.) and nine other congressmen went to Munich, Germany, just before Christmas. Trips to the Far East, South America and Africa still are on the drawing boards, but their numbers are far fewer than in past years.

Over the years, defeated congressmen have used the trips to enjoy one last splash of high living at the expense of the taxpayer. Congress has put a stop to that practice, however.

A new House rule pushed through by Rep. Robert Michel (R-Ill.) prohibits lame ducks from traveling overseas after Election Day. Congressmen who chose not to run for reelection were forbidden to travel at taxpayer expense after Congress adjourned on Dec. 16.

A similar rule was adopted in the Senate in 1979 under the sponsorship of Sen. Gaylord Nelson (D-Wis.).

"The fact Congress remained in session until nine days before Christmas made it difficult to schedule any trips before Christmas," said John Brady, chief of staff of the House Foreign Affairs Committee.

"The 97th Congress will open Jan. 5, right after the holidays, and that makes scheduling difficult, also."

However, that doesn't mean members of the Foreign Affairs Committee won't have a chance to junket. A trip including stops in Jamaica, Argentina, Brazil, Peru and Costa Rica is being planned for Jan. 7 through Jan. 18.

The trip will be headed by Rep. Clement Zablocki (D-Wis.), committee chairman, and Rep. Gus Yatron (D-Pa.), chairman of the Inter-American Affiars subcommittee. Ten other members are expected to join them, but Brady would not say who.

"The plans are not final, but when they are, we will announce the names," he said.

Another trip, to Africa, is being planned by six members of the committtee for the Afro-American Organization about Jan. 7.

Whether the congressmen will have government transportation for their trips is not clear, and that is another reason why junkets have been held down this year.

Most congressional junkets usually are provided with the Navy or Air Force equivalent of the 727 jetliner, but the military says their places aren't available this year.

"We have no aircraft scheduled for congressional travel at this point," a Defense Department spokesman said. "In fact, during this period of limbo between the Carter and Reagan administrations, we are not assigning any aircraft for such purposes. I don't know how long that will continue or whether it will change by Jan. 7."

The trip taken in December by Shuster's group to attend the German-American Parliamentary Conference in Munich was taken by commercial aircraft.

Sponsored by the American Heritage Foundation and the German Hanns Seidel Foundation, the conference was attended by Shuster and Reps. Charles Grassley (R-Iowa), Robert Badham (R-Calif.), Ed Bethune (R-Ark.), Marjorie Holt (R-Md.), Ken Kramer (R-Colo.), Toby Roth (R-Wis.), Jim Santini (D-Nev.), Charles Stenholm (D-Tex.), and Robert Walker (R-Pa.).

The Senate Foreign Relations Committee, usually one of the most active in scheduling junkets, has planned few trips this time.

Sen. Charles Percy (R-Ill.), who will become chairman of the committee in the 97th Congress, went to Moscow from Nov. 21 through 28, and Sen. John Glenn (D-Ohio), chairman of the subcommittee on East Asian and Pacific affairs, is planning a trip to the Far East in January, but those are the only trips announced by the committee.

Some committees, however, decline to discuss senators' junkets.