The State Department yesterday canceled its warning to U.S. travelers that they risk the "potential danger of terrorist acts" if they use the airport at Athens.

The advisory was issued June 18, four days after Trans World Airlines Flight 847 was hijacked after leaving Athens for Rome. The advisory imposed an economic burden on the Greeks, and Greek officials started a lobbying campaign here about two weeks ago to have the advisory lifted after thousands of U.S. citizens canceled planned vacations in Greece.

Charles Redman, deputy State Department spokesman, said the revocation of the travel advisory "follows a careful inspection of Athens International Airport by a team composed of FAA airport security experts last week. The team found that the Greek government had taken positive actions, which are ongoing, to improve airport security and that Athens International Airport now meets international airport security requirements."

Redman declined to list specific improvements, but said that the Greek government "was positive and responsive to the concerns which we expressed." U.S. concerns centered on three areas: screening of passengers and their carry-on baggage, screening of ground personnel and security of the airport perimeter.

Transportation Secretary Elizabeth Hanford Dole said, "I want to assure all Americans that we will continue to monitor security arrangements at Athens and other international airports." Since the hijacking to Beirut, Federal Aviation Administration monitoring teams have been surveying airports around the world.

Stavros Frangopoulos, press counselor at the Greek Embassy here, said, "We don't have an official reaction from our government yet, but we are very pleased. We applaud the decision."

White House spokesman Larry Speakes was asked at yesterday's midday briefing about the status of Beirut International Airport, which the Reagan administration has sought to isolate by prohibiting flights between the United States and Lebanon and banning the sale of tickets to Lebanon. Speakes said that some security improvements have been made at the airport, but that the administration wants more.

The hijacked TWA plane is still held in Beirut. A Shiite Amal militia spokesman said Saturday that the jet will be held "until we feel comfortable" that the United States will not punish Lebanon for the hijacking, in which one American was killed.