Whether the two Americans killed in Nicaragua Saturday used airstrips built or controlled by the U.S. government in Honduras to engage in combat operations looms night as a potentially explosive political question for the Reagan administration.

Sen. Patrick J. Leahy (D-Vt.) said in an telephone interview last night that, as a member of the Senate Select Committee on Intelligence, he will demand that the question be explored with the Central Intelligence Agency and other government agencies.

Leahy's expression of concern came as Nicaragua's Sandinista government officials released maps that they said were recovered from the site where the UH500 helicopter carrying the two Americans, Dana H. Parker and James P. Powell III, crashed.

Hand-drawn air routes on the map included one from Jamastran, Honduras, to Santa Clara, Nicaragua, the Sandinistas said in Managua, adding that the downed helicopter used that route. Anti-government "contra" rebels denied that. The Reagan administration requested money last year to improve the dirt airstrip at Jamastran.

The Sandinistas said the map was recovered from a body at the crash site and also showed a route drawn from the big U.S. airstrip in El Aguacate, Honduras, asserting that the helicopter departed from that U.S.-controlled base.

Leahy said that, if the U.S. government were allowing Americans to launch combat operations into Nicaragua from bases it controls in Honduras, "it would violate every single thing that the administration has told us."

Leahy added that another part of his inquiry would be into whether the CIA or some other U.S. government agency is facilitating American civilians' way into combat in Nicaragua.

"I want to make sure we're not getting into one of those wink-and-shrug situations where somebody from the government says, 'We really can't hire you, but you go down the street and see Jose and tell him Joe Smith sent you.' That's what I'm concerned with," he said.

Officials of the Alabama National Guard, where Parker was a captain in the Special Forces Group, yesterday refused to give any details about him, saying they had been told to refer all questions to the National Guard Bureau in the Pentagon.

The bureau first said it had been told by the Defense Department not to discuss Parker because it would be "inappropriate" until next of kin were notified.

The Pentagon last night finally confirmed that Parker was a captain in the 1st Battalion of the Special Forces Group at Decatur. He was not on Guard duty at the time of his death, a Pentagon official added.