Britain's top law enforcement official, Home Secretary John Reid, said civil liberties "must and will be balanced by the right of collective security."
Police, meanwhile, examined several homes and businesses for clues into the alleged plot broken up Thursday. Another suspect was arrested Tuesday, bringing the number being detained to 24.
The hearing scheduled for Wednesday afternoon addresses the cases of 22 suspects arrested in the initial sweep. Under new terrorism laws, the suspects can be held for 28 days as investigators prepare charges.
"What the police do not want to do is bring serious charges which then collapse," reports CBS News correspondent Sheila MacVicar. "There is concern police were pushed to disrupt the plot before they had enough firm evidence."
The hearing was being held at a secret location, under tight security.
"The police are seriously worried that something could leak out that would prejudice their case should it eventually come to court," reports CBS News correspondent Larry Miller. "So secret is this that the evidence is being given via a live video link."
Air service nudged closer to normal. British Airways said it planned to operate 90 percent of scheduled services from Heathrow airport on Wednesday and resume a full schedule Friday.
Concern about security rose after a 12-year-old boy managed to board a plane at Gatwick Airport on Tuesday without a passport, ticket or boarding pass. He was detected by the cabin crew and removed before the flight took off.
"The boy had passed through a full security screening process and we are confident there was no threat to passengers, staff or the aircraft at any time," said Stewart McDonald, spokesman the airport's owner, BAA PLC.
Meanwhile, Reid met Wednesday morning with European interior ministers and agreed to do greater research into new types of explosives, including liquid explosives, reports Miller.
Anti-terror laws passed after the July 7, 2005, London transit bombings give the government up to four weeks to hold suspects without charge, but they must periodically go before a judge to make a case for continued confinement. The accused person is represented by lawyers and does not appear in court.
Amjad Sarwar said his brother, Assad, was one of the people arrested in High Wycombe, west of London. He said Assad is not involved in terrorism.
"They've got it all wrong," Sarwar told Britain's Channel 4. "He is an innocent guy. He minds his own business. He's been helping the youth out considerably in the area, and he's got nothing to do with it.
"There is no way he could have anything to do with terrorism. He condemns terrorism."
A Metropolitan Police spokeswoman said that 46 locations, including businesses and homes, have been searched. Three Internet cafes were raided in the towns of Slough and Reading the same day the first arrests were made, a spokesman for Thames Valley Police said.
Officers have not officially disclosed details about any items recovered during the searches.
The British Broadcasting Corp. reported that a search of the woodland area in High Wycombe turned up several firearms and other items of interest. It was not clear if they were to be used in the alleged jetliner plot, which authorities say involved a plan to smuggle liquid explosives hidden in hand luggage aboard flights.
Halfway around the world, investigations continued in Pakistan, where authorities held 17 people, including British citizen Rashid Rauf, who they said has al Qaeda connections and was a key player in the plot. At least one of Rauf's brothers was arrested in England during the sweep.
Pakistan's Foreign Ministry said the country may extradite Rauf to Britain but had not been asked.
The investigation was colored by claims that Britain's government has talked tough regarding terrorism but has been slow to act.
Conservative Party leader David Cameron said Prime Minister Tony Blair failed to follow through on a plan unveiled after last year's transit bombings to crack down on radical clerics and help Britain's moderate Muslims face down militants in their communities.
"We need follow-through when the headlines have moved on," Cameron said. "But precious little has actually been done."