Judges found that the man, who was in regular contact with the terrorism suspect on a mobile number known only to his close friends, and had lent the suspect €2,000, was too much of a security risk to work in sensitive areas at the airport.
The man had first come to police attention after being fined for a minor traffic offence, which was flagged up in the regular checks they make on airport staff.
Federal prosecutors then notified them of his relationship with a suspect under investigation for membership of the foreign terrorist organization Islamic State (Isis).
In court, the airport worker argued that because his friend hadn't been convicted of anything, the assumption of innocence should apply to him as well.
But the judge said that he had no automatic right to be declared reliable by the state of Hesse.
He added that the man's refusal to acknowledge guilt over the traffic offence and apparent close relationship with the suspected Isis supporter – a colleague and school friend – were enough to justify the airport authorities' decision.
Since the airport worker was unable to convince the judge that he didn't know about his friend's radical views, the judge upheld the police decision under the Air Safety Law (Luftsicherheitsgesetz) – one of Germany's strictest regulations.
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