A seventh suspect has been arrested over a break-in at RAF Brize Norton during which two military aircraft were damaged.
The 22-year-old man was detained on Friday in Bedford on suspicion of the commission, preparation or instigation of acts of terrorism.
The incident saw activists break into the Oxfordshire air base and spray paint on two RAF Voyager planes, causing £7million worth of damage.
Palestine Action, which has since been proscribed under terrorism legislation, said it was behind the incident.
Last month, four people were charged and remanded in custody over the break-in
in June. A 41-year-old woman was released on bail, while a man was freed without charge.
Footage from the incident showed two people inside the base at night. One could be seen riding a scooter up to a Voyager and spraying paint into its jet engine.
Palestine Action also said activists had used crowbars to damage planes.
The Government moved to proscribe the group under anti-terror laws after the group claimed responsibility for the action.
Some 81 organisations have been proscribed under the 2000 Act, including Islamist terrorist groups such as Hamas and al Qaida, far-right groups such as National Action, and Russian private military company Wagner Group.
Another 14 organisations connected with Northern Ireland are also banned under previous legislation, including the IRA and UDA.
