Police said no charges would be filed against the two men, who were identified only as a 24-year-old and a 27-year-old. Scottish police arrested them at the Royal Alexandra Hospital, in Paisley, Glasgow, during the aftermath of the failed attacks.
Bilal Abdullah, a 27-year-old doctor who was charged last week by British police with conspiring to set off explosions, worked at the same hospital.
On Saturday, police charged two doctors in connection with failed attacks and a judge also gave investigators an additional week to question a Jordanian doctor suspected of playing a role in the attacks.
A total of three people have now been charged since a pair of cars packed with gas cylinders and nails were found in central London on June 29. The next day, two men crashed a flaming Jeep Cherokee loaded with gas canisters and gasoline into security barriers at Glasgow airport's main terminal.
Indian doctor Sabeel Ahmed, 26, was charged Saturday with withholding information that could prevent an act of terrorism.
His brother, Kafeel Ahmed, is believed to have set himself ablaze after crashing into the airport and remains in a Scottish hospital with critical burns. Sabeel Ahmed was arrested in Liverpool the day of the Glasgow attack and is due to appear in a London court on Monday.
Muhammad Haneef, 27, a distant cousin who once shared a house with the brothers in Britain, was charged Saturday in Brisbane, Australia, with supporting a terrorist group.
A British judge also gave police until July 21 to continue questioning a Jordanian doctor, Mohammed Asha, 26, who was detained on a northern England highway on June 30. He was detained with his wife, Marwa Asha, who was released Thursday without charge. Under British terrorism laws, police must charge him within 28 days of his arrest.