The 21-year-old from Birmingham in central England was arrested after his flight landed on yesterday afternoon at London's Gatwick airport, police said.
"The case is not connected to Monday's arrests" of two men from Birmingham at London's Heathrow airport, police said yesterday.
Those men, both 21, had also flown back from Istanbul.
They were held on suspicion of terrorism offences linked to Syria. Police said they were believed to have travelled to the conflict-ravaged country in May 2013.
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British police have over the past three years arrested a number of people who have travelled to Syria over concerns that they are fighting with jihadi groups.
Foreign Secretary William Hague said on Monday that "hundreds" of Britons were believed to have gone to fight in Syria but said security forces were doing their best to monitor the situation.
In November British prosecutors dropped a case against a doctor accused of kidnapping a British photographer and his Dutch colleague in Syria.