A district court judge ordered Kerim Sadok Chatty, 29, detained on preliminary charges of planning to hijack a plane and illegal possession of a weapon, but he rejected counts of planning to sabotage an airplane or airport.
Investigators have said they are in contact with foreign authorities and are looking for links between Chatty and terror groups, along with other lines of investigation.
But prosecutor Thomas Haeggstroem said the motive was still being investigated and he avoided any suggestion of a link between the suspect and any broader plots or terrorism.
"I have no evidence concerning crashing the aircraft," Haeggstroem said, declining to offer more details.
In a gray T-shirt and with his head shaved, Chatty spent ninety minutes in a court hearing that was closed to the public. As CBS News Correspondent Richard Rothreports, the Swedish Muslim was ordered held for two weeks.
Judge Thomas Wallin then closed the 90-minute hearing to the public on the prosecution's request before allowing reporters back in to hear his decision. It was not immediately clear why charges of sabotage that had been requested by the prosecution were not included.
According to the prosecutor, "He is a suspect on probable cause on preparation of hijacking and unlawful possession of a gun.
Chatty's arrest in Sweden occurred as he was about to board a Ryanair jet bound for London to attend an Islamic conference in Birmingham, England when a routine security check turned up a pistol in his hand luggage. Since then, officials have said they're investigating possible links with terror groups though his lawyer says Chatty denies everything but the gun charge.
Chatty's lawyer, Nils Uggla, said Sunday that Chatty - a Muslim convert whose mother is Swedish and father is Tunisian - can explain why he had the gun in his bag.
Uggla says, "He has an explanation of why he had his gun and that is enough for me."
But he's not saying what the explanation is -- and Chatty's background has authorities looking deeper. He's 29 with a criminal past and a history of violence. He's also a recent convert to Islam who found religion in jail.
On top of that, he took flight training in the U.S., though chatty was recruited by the flight school he attended; he trained years before the Sept. 11 hijackers took their flight courses in the U.S. and he flunked out.
The North American Institute of Aviation says, "He didn't get to the multi engine training; he was probably gone before that, he might have been flying in a smaller plane."
Swedish officials have strongly denied reports Chatty wanted to crash the Ryanair jet into an American embassy in Europe, but the incident is ringing alarm bells, in the run-up to Sept. 11.
Magnus Ranstorp of the Center for the Study of Terrorism says, "Anything that will happen in and around this period is going to cause alarm, is going to cause confusion."
In fact, a security expert here says it already has everyone in European law enforcement looking over their shoulders.
Chief Prosecutor Thomas Haggstrom told the court that Chatty, 29, was accused of "planning a hijack," "aviation sabotage," weapons offenses and "serious crime."
Classifying the alleged offences as "serious crime" showed new evidence had emerged since Chatty was seized as he was boarding a Ryanair flight from Vasteras, a small town 60 miles west of Stockholm, to Britain.
Intelligence sources have said the suspect intended to hijack the plane and crash it into a U.S. embassy in Europe, but this has been denied by a top security police official.
"This is a very, very serious crime and very unusual in Sweden," police spokesman Ulf Palm told reporters. "Off hand, I can't think of a similar incident in Sweden."
The Swedish Criminal Code's section on aviation defines aviation sabotage, if classed as serious crime, as "endangering the lives of many people," Bengt Larsson, legal adviser to the Swedish Civil Aviation Administration, told Reuters.
Swedish investigators did not believe Chatty or any possible accomplices were connected to al Qaeda, the sources said. Instead they believe a copycat attack was being planned.
Chatty's relatives said he opposed violence and were confident he had a reason for carrying the gun that had nothing to do with hijacking plans.
"The investigations will finally show that he's innocent," his father, Sadok, said Sunday before slamming the door closed at his apartment in a small town midway between Vaesteraas and Stockholm.
Sarah Chatty remembered how excited her brother was about going to the school and said he had a good time and made lots of friends.
"It was just a hobby," the 19-year-old physical fitness student said. "Like I want to dance, he wanted to fly."
She hasn't spoken to her brother since the arrest but insisted the gun "had nothing to do with terrorism."