The AFL-CIO's top political operatives concluded three days of closed-door sessions today, saying they are convinced that, despite President Reagan's landslide reelection, Democrats can regain control of the Senate in 1986 and recapture the White House in 1988.

Organized labor, which raised unprecedented amounts of money in its biggest political effort ever last year, is prepared to target about 10 Senate seats it believes that Democrats can regain from conservative Republicans elected by slim margins in 1980.

"Our aim is a liberal majority in the Senate . . . . We think it can be done," said Murray Seeger, director of information for the 13 million member federation.

No formal labor endorsements will be made until state AFL-CIOs make their decisions, but the federation's Committee on Political Education (COPE) has prepared a list of Republicans facing reelection, their victory margins and their labor voting record.

Republicans, who control the Senate with 53 seats, have 22 senators facing reelection in 1986, while Democrats have 12.

Labor plans to target Senate Republicans considered most beatable and most "ultraconservative," based on the COPE voting records. According to COPE sources, these are the most likely targets, their 1980 election vote percentage and their labor vote percentage:

Jeremiah Denton (Ala.), 50.2 percent and 7 percent; John P. East (N.C.), 50 percent and 3 percent; Mack Mattingly (Ga.), 50.9 percent and 7 percent; Steve Symms (Idaho), 49.7 percent and 3 percent; Don Nickles (Okla.), 53.5 percent and 3 percent; Dan Quayle (Ind.), 53.8 percent and 10 percent, and Charles E. Grassley (Iowa), 53.5 percent and 11 percent.