The arrest sparked a backlash from some public figures and politicians, and prompted a fierce debate about policing and free speech.
Recalling his flight, which landed in the UK on 1 September, he said he "realised something was up" when no one on the plane was allowed to stand up.
"I didn't expect it to be what it turned out to be. And then they called my name out and I think I immediately knew what was going to happen," he said.
He was then met by five armed police officers, who explained he was going to be arrested because of his online posts.
He said he had a strong reaction to being arrested because "for eight years I've been harassed, often by the same small group of men, but also by a wider community online".