WASHINGTON – While Secretary of State Rice fends off questioning in Europe over CIA-run air flights of prisoners in the war on terror, some analysts outside the CIA are asking how the flights were exposed so easily.

The CIA’s legendary capacity for stealth, celebrated in so many cloak-and-dagger books and films, seems to have been all but absent as hooded prisoners were zipped from one airport to another by agency airplanes, a journalist who helped prepare one of the first detailed reports on the air transfer program said.

“I would say they didn’t give a damn,” Fredrik Laurin, a producer with a Swedish television show, “Kalla Fakta,” or “Cold Facts,” said when asked what priority the agency gave to keeping the air operation secret. “If I was an American taxpayer, I would be upset,” Mr. Laurin said in a telephone interview from Sweden yesterday.

In May 2004, the Swedish show reported on the CIA’s involvement with the expulsion of two men from Sweden to Egypt in December 2001. The tail number of an aircraft involved in the transfer led quickly to information about at least six other occasions on which the same small Gulfstream V jet was used to move prisoners from various locations to countries such as Egypt, Jordan, and Syria. “Once we had the identity of the plane, which we were able to find out in many ways – a plane leaves a lot of traces – it was obvious the plane was fishy,” Mr. Laurin said.

When a producer working on the broadcast called one of the American firms involved in leasing the plane, the call was returned 15 minutes later by the Swedish intelligence service, which said it was calling at the request of its “U.S. cooperation partners.”

Mr. Laurin said almost every name linked to the company that appeared to own the aircraft, Premiere Executive Transport Services Incorporated of Dedham, Mass., seemed to be fake. “You weren’t able to trace the name to any living individual,” he said. “They were all living in post office boxes in Virginia.”

“I must say, if that’s all the imagination they can drum up at Langley, I’d fire the bunch,” Mr. Laurin said.

Other journalists and human rights groups soon found that the movements of CIA aircraft could be traced with relative ease, using government records and a loose network of aviation buffs known as planespotters. A May 2005 report in the New York Times sketched out the CIA’s aviation program in even greater detail and called the companies’ cover “surprisingly thin.” Later, the newspaper said it found 26 CIA-connected planes carried out at least 307 flights in Europe since September 2001.

A Washington Post story last month about the prisoner flights and their connection to CIA-operated prisons in Eastern Europe triggered howls of outrage from some Europeans, a formal inquiry from the European Union, and almost daily stories in European publications cataloging CIA flights to or through specific countries.

Anger over the CIA air program has hurt America’s image overseas and roiled Ms. Rice’s trip. Before leaving for Europe on Monday, she defended the use of so-called renditions as a “vital tool in combating transnational terrorism.” Ms. Rice has declined to discuss details of the renditions, which often involve terrorism suspects who could not be prosecuted in America for various reasons.

Ms. Rice said the procedure has foiled terrorists who targeted Americans and Europeans. “We’re all in this together,” Ms. Rice said. “Very often these are not plots that are headed for the United States; they’re headed for somewhere in Europe.”

A spokeswoman for the CIA said the agency had no comment on the prisoner rendition program. An official did confirm that leaks in the Washington Post story have been referred to the Justice Department for investigation.

Several longtime analysts of the CIA’s operations said the agency needs to investigate how its own tactics permitted the prisoner-transfer flights to become so widely publicized.

“It’s bad tradecraft. It’s very bad tradecraft,” John Pike, the executive director of a group that studies secret government operations, GlobalSecurity.org, said. “You just have to wonder what it is they thought they were doing.”

Mr. Pike described the arrangements to obscure the ownership of the aircraft involved as “amazingly flimsy.”

“If they had decent cover for this thing, this wouldn’t have happened,” he said. “All they had to do was bury these planes inside a real charter company that actually did have an office where you could walk in and charter an airplane.”

A former head of the CIA’s counterterrorism center, Vincent Cannistraro, said that the prisoner pick ups and drop-offs would not have been considered highly covert because officials in the host countries were aware of the operations. “They weren’t, in that sense, clandestine flights,” he said. “I’d suspect they didn’t believe they needed a lot of tradecraft.”

Mr. Cannistraro said he believes that news reports are exaggerating the number of prisoner transfers by suggesting that every flight the CIA linked planes made since September 11, 2001, was related to a rendition. However, he said the agency appeared not to appreciate how public knowledge of the flights would spawn questions and news reports like the recent Washington Post story about the secret prisons. The flight schedules helped Human Rights Watch, an advocacy group critical of the Bush administration’s treatment of detainees, pinpoint Romania and Poland as likely locations for the facilities.

“People are putting the two together,” Mr. Cannistraro said. “In a democratic society, you have a democratic press following these kinds of things with some kind of energy.”

The agency may also have misjudged the way the Internet allows journalists, human rights activists, and the hobbyists who spot planes at airports, to pool their information in a way that would have been impossible even a decade ago.

“Certainly, an operation of this kind is harder to do than it ever was in the past simply because you have so many people watching and communicating instantly around the globe,” an intelligence analyst at the Federation of American Scientists, Steven Aftergood, said. He called the disclosures “a breach of operational security” and said he believes the CIA has already changed its procedures as a result.

Mr. Aftergood said the secrecy of the program may also have been doomed by the sharp increase in the frequency of renditions after September 11, 2001. “This is an ambitious program that crosses many geographical and political boundaries. As such, it’s very difficult to keep secret indefinitely,” the analyst said. He noted that some conservatives believe some in the CIA who are disgruntled with the Bush administration are deliberately leaking information in order to shut down certain programs. Mr. Aftergood said he did not believe that was the case with the renditions program.

An official at Human Rights Watch, John Sifton, said intelligence agencies have never done a particularly good job at keeping long-running programs under wraps. “The deck is stacked against secrecy,” he observed.