Two people have been released without charge after being questioned by police over an alleged plot to blow up jets.
Tanvir Hussain, Adam Khatib and Assad Ali Sarwar in court
They were freed at 1920 BST and 2300 BST on Wednesday. Police were given more time to quiz nine other suspects. Eight can be held for seven more days.
And police have until Thursday evening to quiz the ninth, named as Umair Hussain, 24, from east London.
Eleven other suspects, who have been charged, appeared in court in London on Tuesday and were remanded in custody.
Tim Rustem, lawyer for Umair Hussain, said he was glad the High Court judge had only granted police 24 hours to question his client, saying the case against him was "circumstantial".
He said new anti-terrorism laws were "strong" and were "effectively a check on the investigative powers" of the police.
"It's good to see the High Court judge being able to differentiate between different cases," he said.
Umair Hussain's brother, 23-year-old Mehran Hussain, has already been charged in relation to the investigation.
Anti-terror police searched a wood at Lane End, Buckinghamshire, overnight following a previous search of woods eight miles away in High Wycombe.
Of the 11 people already charged, eight were accused of conspiracy to murder and preparing acts of terrorism.
Two were accused of failing to disclose information and a 17-year-old was charged with possessing articles useful to a person preparing terrorism acts.
They all deny the charges.
Eight of the people who appeared at City of Westminster Magistrates' Court were remanded in custody until 4 September when they will appear at the Old Bailey.
- Tanvir Hussain, 25, of Leyton, east London
- Umar Islam, 28, of Stratford, east London
- Arafat Waheed Khan, 25, of Walthamstow, east London
- Ahmed Abdullah Ali, 25, of Walthamstow
- Ibrahim Savant, 25, of London N16
- Waheed Zaman, 22, of Walthamstow
- Assad Ali Sarwar, 26, of High Wycombe
- Adam Khatib, 19, of Walthamstow
They were charged with conspiracy to murder and with preparing acts of terrorism under section five of the Terrorism Act 2006.
Another man, Mehran Hussain, of Chingford, east London, and Cossar Ali - a 23-year-old mother of an eight-month-old baby of Walthamstow, east London - were charged with failing to disclose information. They were remanded until 19 September.
A 17-year-old boy, accused of possessing a book on bombs, suicide notes and the wills of people prepared to commit terrorist acts, was remanded until 29 August.
The group were arrested in police raids in Walthamstow, east London, High Wycombe in Buckinghamshire and Birmingham on 10 August.
Security at airports was increased, causing widespread flight cancellations in the UK for several days.