Relatives of MIAs optimistic in search for answers

A delegation representing relatives of United States servicemen missing in action in Indochina expressed optimism that Laos will cooperate in the search for traces of MIAs, some of whom may still be alive. Group members expect less progress in Vietnam.

The four-person delegation from the National League of Families returned recently from two weeks in Laos and Vietnam. The league's executive director, Ann Griffiths, said the group plans to ask the US government to review American Indochina policy ''to see whether it has accomplished either our strategic or POW-MIA objectives.''

The delegation is convinced that some Americans may still by alive in capitivity in Indochina. Group members say they were told by a senior official of the Laos Interior Ministry that ''it is possible'' prisoners are being held in remote areas of the country, unknown to the government, by people who are unaware the Vietnam war is over.

Delegation members felt that the Laotian government might be willing to allow joint US-Laos search-and-recovery missions to investigate crash sites. If this happened, Mrs. Griffiths added, the league would try to encourage small aid projects directly benefiting the inhabitants of the immediate vicinity of sites.

Although talks in Hanoi were quite friendly, the delegation said it was told by Vietnamese officials that the present US policy toward Hanoi remained ''the principal obstacle'' to any resolution of the MIA problem. Officials did, however, allow the delegation and accompanying American journalists unlimited time in the capital's war museum, where they noted and filmed documents, identification cards, and photographs on exhibit.

In southern Laos the group went to a crash site where a C-130 gunship is believed to have crashed, killing 13 crew members, among them the husband of delegation member Ann Hart. Accompanied by a US diplomat, the group was also taken to a cave in northern Laos where two Americans were said to have died of natural causes in 1968. Before housing the prisoners, the cave had been the living quarters of the Pathet Lao leader Prince Souphanouvong.