The sighting, which was highlighted last week by the UK Airprox Board, is said to have occurred during an air-to-air refuelling mission over the North Sea at Cromer in February. The UK Airprox Board reports on incidents to improve air safety, covering near misses and unidentified objects. One of the pilots in the tanker ducked as the object whizzed by. The other pilot in the fighter jet, which was being refuelled, also claimed to have seen the unidentified object. The refuelling mission was taking part at 16,000ft at the time.