Searchers had picked up standard airplane emergency equipment, a cargo pallet and two buoys, and initial reports suggested the items might have been from the crashed plane.
But later, Brazilian military officials said debris recovered so far was not from the missing Airbus. For one thing, the plane was not carrying wooden luggage pallets, The Associated Press reported.
"No material from the flight was removed," Brazilian Air Force Gen. Ramon Cardoso said. "What we saw was debris that belonged to some aircraft that were left behind because we have a priority on the search [for] bodies. But so far, no piece of the aircraft has been found."
The oil slick spotted yesterday near the wooden pallets was not from the plane either, "So much oil could not belong to the aircraft," Cardoso said.
Brazilian authorities do, however, still believe to have located parts of the plane although they have not yet pulled them out of the ocean.
They spotted Wednesday a 23-foot (seven-meter) chunk of plane, an airline seat and several large brown and yellow pieces that likely came from inside the plane, military officials said.
There is still no clear explanation as to exactly what brought Air France Flight 447 down on its route from Rio de Janeiro to Paris.
"The United States of America, Spain, Canada, all the world is sharing their means which these countries are making available so that we can quickly have some answers" French Foreign Minister Bernard Kouchner told reporters last night.
"At the moment, in the hour I'm speaking to you right now, there are no answers" he added.
No concrete answers as to the cause of the crash can be given until the plane's voice and data recorders or black boxes are found.
Kouchner did not categorically rule out terrorism as a cause, "Nothing leads us to believe that there was an explosion, but that doesn't mean there wasn't one. Once again, all the paths are open and we will not give priority to a single premise because that would be immoral."
As the search for bodies and debris continued, there were suggestions the speed of the plane may have been a factor in the accident, according to new information released Thursday.
It's too early to know for sure, but the plane's maker, Airbus, is now reminding pilots and crew who fly each and every one of its planes to follow correct procedures if they are facing unreliable speed indications or data.
Airbus issued a statement Thursday reminding airlines that if such a scenario occurs, pilots should maintain their power, level off if necessary and start troubleshooting.
The alert came after French investigators reported that automatic maintenance messages sent from the plane indicated inconsistent airspeeds, which may mean systems that tell the computers how fast the plane was flying weren't all working properly.
The memo went out regarding all types of Airbus planes. Every major U.S. carrier flies Airbus planes except for Southwest and Continental.
The latest development may provide another piece of the puzzle regarding the mystery behind what happened when Flight 447 vanished some 700 miles off Brazil's coast with 228 people on board.
It was initially believed the debris recovered by a helicopter might provide more clues in the mystery, but that debris turned out to be unrelated to the flight.
Officials were trying to get their hands on additional bits of wreckage -- including pieces that appeared to be from the inside of the plane's cabin. More teams with sophisticated equipment to recover underwater remnants are on the way.
Two separate large fields of debris, including what appeared to be a 23-foot-long piece of a plane, were spotted Tuesday about 60 miles apart in the Atlantic. Those two areas of apparent plane remnants caused some to suggest the Airbus broke up in midair.
"It almost couldn't occur unless your plane came apart in flight," said ABC News aviation consultant John Nance today.
"If the plane broke up in midair at altitude, then it's going to be covering a really large piece of real estate," said Robert Ballard, the scientist who discovered the wreck of the Titanic. "So it becomes a strategy of working within a debris field, trying to figure the physics of it."
Flight 447's Automated Messages
Flight 447 from Rio de Janeiro to Paris vanished Sunday night, about four hours into its journey.
Before it disappeared, failures in the plane's systems began to generate automated maintenance messages that were sent to the airline 10 minutes after the pilots sent a text message to Air France indicating they were encountering turbulence and thunderstorms.
The automatic messages, received during the course of three minutes, indicated a growing series of electrical and equipment failures just before the plane disappeared, according to published reports. Some reports suggest the aircraft flew through electrically charged clouds and 100-mile-per-hour winds.
"One of the things that puzzle me, and I think a lot of us, is the fact that we have 10 minutes that elapsed between the time the crew reported they were flying around cumulus nimbus buildups and the time this unraveling sequence began," Nance said. "But there's one lesson from a lot of history of aviation accident investigations, and that is: It can look like two things are connected when, in fact, they aren't."
"There's a period where you see many systems degrading very, very quickly, which again starts making you think that there was something major going on with the airplane," said William Voss, director of the Flight Safety Foundation.
"Everything has at least one or two levels of backup and so something had to happen that started pulling these things offline one after the other because otherwise the aircraft would have been able to continue and at least be able to get to a diversion airport," Voss added.
Air France Flight 447: The Search for Black Boxes
Ballard, now director of the Center for Ocean Exploration and Archeological Oceanography at the University of Rhode Island, said those ocean conditions could present a major challenge.
"The terrain here is worse than the terrain where we lost the Titanic," Ballard said. "The Titanic is sort of like in the Badlands of the Dakotas compared to the Rocky Mountains."
The black boxes, the size of a proverbial bread box, can survive in up to 20,000 feet of water, and they emit a pinging sound. But water temperatures can affect the distance that sound travels, and the mountainous ocean floor can block the signal, which is only guaranteed to last about 26 more days.
The information the black boxes hold is critical: The cockpit voice recorder would have the last two hours of conversation recorded; the flight data recorder could hold information about as many as 400 systems on the plane to help investigators piece together the puzzle.
"We have to find that," Nance said. "This is a whole new class of airplane, not just the Airbus, but Boeings like it. We have to know what happened."
"It's down there," Nance said. "It'll be mangled, but it's down there."
"If they can't get that black box, they've got quite a detective story to sort out to try to determine the cause," Ballard said.
U.S. accident investigators have been asked to assist in the recovery effort. Several other teams of people on planes and ships are also making their way to the remote crash site some 400 miles from Brazil's Fernando de Noronha islands, carrying equipment to recover debris. A French search and exploration ship, due on site Friday, is equipped with robots that can plunge about 20,000 feet underwater to help recover wreckage.
"Heavy objects will go to the bottom very, very rapidly," Ballard said. "Lighter objects are carried for great distances, much like the lifeboats of the Titanic were miles and miles away from where we actually found the Titanic. And in many ways, the debris they're finding are like the lifeboats of the Titanic, floating on the surface, being carried further and further."
But recovering debris in this part of the ocean may not be easy.
"That's like searching for an airplane in the surface of the mountains. You could be very close and not be able to see the wreckage," said John Hansman, a professor of aeronautics and astronautics at the Massachusetts Institute of Technology.
Missing Plane Faced Bad Weather
"There is never, ever just one cause to an airline accident," Nance said. "Never has been, never will be."
Developments this week have confirmed the complexity of the puzzle as searchers pinpoint debris and assess the weather.
"I can't remember an accident in quite some time, if ever, that has raised the level of concern in the pilot community as much as this one has," Nance said.
"Those of us who are pilots are really apprehensive about what happened here because when you're out over the water at altitude, this sort of thing is never supposed to happen," he added.
Confirmed by the pilot's message, the plane is thought to have encountered severe thunderstorms and lightning or a combination of both. The four-year-old Airbus jet did have sophisticated radar that should have helped the pilots try to skirt any violent weather.
French Transport Minister Jean-Louis Borloo said Tuesday he did not believe bad weather alone could have brought the plane down. He also brushed off the idea that terrorism or a hijacking could be involved.
Still, Ken Reeves, director of forecasting operations at Accuweather.com, said towering thunderstorms, fairly common over that area of the Atlantic, could have been a challenge.
"These storms go up and down at a fairly rapid rate, and so they can develop in the course of minutes," Reeves said. "They don't take hours or even days to develop. And they can diminish in the course of minutes as well. That makes the decision of the pilot ever so difficult determining whether to go around or through."
Reeves added, "Once you make that decision, unfortunately, many times you're committed, because you cannot turn back around because the storm may develop in front of you and behind you as well and you're kind of caught in the middle with nowhere to go but straight forward."
On Monday night a crew from TAM, Brazil's largest air carrier, said it saw orange spots on the ocean while flying over the same general area as Air France Flight 447.
On Tuesday searchers found an oil slick and debris from the plane floating in the Atlantic.
That plane was allowed to take off for Paris after an inspection. There was no known threat against the flight that took off four days later from Rio, then vanished.
Passengers on the plane came from more than 30 countries. Sixty-one French citizens, 58 Brazilians and three Americans were among those onboard, and all 12 crew members were French, according to the airline.
For now, the mystery as to what happened to them onboard remains.
"If you didn't know the Titanic hit an iceberg, and you just went down and looked at the debris that was on the bottom of the ocean, you would have never guessed it was an iceberg," Ballard said. "Because the iceberg did minor damage to the Titanic. It was the sinking process and the pressure on the way down that did most of the destruction."
ABC News' Renata Araujo, Sonia Gallego, Joe Goldman, Christel Kucharz, Luis Martinez, Phoebe Natanson, Gabriel O'Rorke, Samira Parkinson-Smith, Kirit Radia and Christophe Schpoliansky, Reuters and The Associated Press contributed to this report.