Its all true. Here is a copy of the "London Insurers Revised Regulations for War and Related Policy Coverage's."
17th September 2001.
"... in respect of Airports and airport based operators, products manufacturers, ground handlers, general aviation operators.
Following the tragic events of 11th September 2001, there have been many meetings between aviation brokers and representatives of the aviation underwriting market. The position of underwriters following these meetings is as follows:-
Seven (7) days notice of cancellation is being given effective 23.59 GMT 17th September 2001 under the ... section of the policies for all aviation operators ie. airlines, airports and airport based operators, products manufacturers, ground handlers, general aviation and any other companies whose policies include (these sections).
It is not clear at this stage whether it will be possible to reinstate this cover for non-airline customers. We are of course pressing for whatever cover is available, if any, to be reinstated on your behalf and we will keep you fully appraised of developments as they occur."