Police have been granted more time to question four men and a woman held over the suspected car bomb attempts in London and at Glasgow airport.
Dr Abdullah was one of two men arrested at Glasgow airport
The five can now be held for at least another week. Another suspect is in a Glasgow hospital with severe burns, while a man is being held in Australia.
Another man, an Iraqi doctor, was remanded in custody on Saturday at Westminster Magistrates' Court, London.
Bilal Abdullah, 27, is accused of conspiracy to cause explosions.
Police have until Saturday 14 July to quiz Jordanian Dr Mohammed Asha, 26, and his wife, Marwah Dana Asha, 27.
The couple were arrested on the M6 motorway near Sandbach in Cheshire.
Officers also have until 14 July to question Dr Sabeel Ahmed, 26, who is from India and works at Halton Hospital in Cheshire. Dr Ahmed was detained in Liverpool.
Two other men, aged 25 and 28, and thought to be medical students or doctors, were arrested at the Royal Alexandra Hospital, Paisley.
They can now be held by police until 15 July.
Kafeel Ahmed, 27, from Bangalore, India, was arrested along with Dr Abdullah at Glasgow airport, after a Jeep was driven into the doors of the main terminal building and burst into flames on 30 June.
Mr Ahmed is still in a critical condition in a specialist burns unit at Glasgow Royal Infirmary after suffering 90% burns in the incident.
Australian police are holding Dr Mohammed Haneef, an Indian national who was detained at Brisbane Airport.
Dr Abdullah is the first person charged over the suspected attack attempts. The charge, under the 1883 Explosive Substances Act, carries a maximum life sentence.
He is due to appear at the Old Bailey on 27 July.
The airport incident occurred the day after two cars containing petrol, gas cylinders and nails were found in central London.
Although the UK has lowered its terror threat level from "critical" to "severe", police remain on high alert.