Check-in for some flights remained suspended as of this evening while police investigated.
Police have said there is no indication of a terror motive.
The detained suspect's vehicle was registered in Poland, the German NDR broadcaster reported.
Police alleged the man was under the influence of drugs when he drove the Polish-registered vehicle through a gate and onto the apron, German news agency dpa reported. Simple Flying has learnt bomb disposal experts were called to the scene to examine the auto. No one was hurt in the incident.
A Hanover police spokesperson told DW that the man in his mid-20s drove out onto the runway and followed a plane from Greece's Aegean Airlines after it had landed. "A man broke a barrier with a auto and went on the tarmac", Hanover police posted to Twitter.
Emergency services assess the incident
They think he acted alone. Take-offs and landings of planes were suspended.
They couldn't give further information about where he came from because he was not carrying an identity card.
According to Eurocontrol, the airport remains closed until approximately 22:00 UTC. Flight operations are now suspended.
Flights were delayed and diverted as a result of the incident closing the airport.
The global airport in Hannover handles 5.87 million passengers past year, though it isn't one of Germany's top hubs.
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