The airport said on Monday night that the UFO showed up on its radar several times over three hours from 6.30pm to 9.30pm.
Police said in a statement that they were alerted at 6.30pm about a UFO over Bremen and a patrol car also saw the object.
A police helicopter was sent up to try and find the UFO but could not, although the Weser Kurier newspaper reported it could be seen through binoculars from the airport's traffic control tower.
The helicopter search was called off at 8.45pm, according to the police statement.
A flight from Frankfurt had to be cancelled and a second flight from Munich was diverted to Hannover.
Another plane coming from Paris had to stay airborne for a while before it could land.
A Bremen police spokesman said. “We still don’t know what it was, but it was there.” Possible explanations are that it was a drone or a balloon-like aircraft.
On Sunday in the town of Zwickau, Saxony, an initially unidentified aircraft landed on a field behind a house.
Hours later it turned out to be a remote-controlled model airship.
http://www.thelocal.de/20140107/alleged-ufo-disrupts-travel-at-airport-bremen-germany
Site seems credible, the information isn't from some nut case.
Seems like a pretty good sighting.