Could it have possibly been the privately owned Gnat doing a flyby whilst on his way to meet his slot for Waddo?
Seem to remember a similar occurrence last year.
The A18 is already a dangerous road, made even more hazardous by plonkers looking to the skies instead of the road!
Did the diesel fumes cause an accident or a hazzard to other road users? I doubt it very much. A proficient driver would have been concentrating on his or her driving.
Wind your neck in mate and just think yourself lucky to have seen a red something or other in the air free of charge!
Just a thought.... Just another thought.... Does it really bloody matter??
Jet noise (and smoke on) the sound (and smell) of freedom!!