Peter Norris spoke of his "relief" at going home
Peter Norris, 52, from Uxbridge in west London, said the group was stunned when the district attorney told them the charges were of the most serious nature - espionage.
"We couldn't really believe what the guy was saying to us, we couldn't believe where he was coming from," he told BBC Radio 4's Today programme.
"By that time they'd already taken all the films out of our cameras, and most of them were already developed, and they knew there was no photographs taken at Kalamata or any other Greek military airfield."
"They were accusing us of making notes, diagrams. People who didn't have any notes or diagrams were accused of giving psychological support to the rest of us."
'Interesting airforce'
He denied the group had been asking for trouble by plane-spotting in a country known to be sensitive about its military installations.
"We had visited three airfields on the day we were arrested. We had an official invitation from the Hellenic airforce to be at the open days. So to get stopped and be accused of photography was a bit of a shock."
Mr Norris said he and his companions were "relieved" to be home but would now have to tackle the next legal step.
"We are just out on bail obviously. Once we get home we are then going to try to sort out a defence about this and hopefully defend our corner."
Mr Norris said he would probably avoid doing any more plane-spotting in Greece.
He said, however: "The Greek airforce is a very interesting airforce in that it operates a number of aircraft that other airforces in Europe do not operate.
"The most interesting thing about the Greek airforce is they've got lots of very old 1950s and 1960s fighters."
He added that all the information he knew about the airforce was public knowledge and could be read on its own website.