Hello and welcome to HCM,
There are many causes of sudden death.
The preceding history of long flight can have an association with sudden death.
However, the underlying disease is something else which is aggravated by some precipitating factor.
A long distance flight can be that precipitating factor.
Sudden death can occur in situations like myocardial infarction
, stroke, pulmonary embolism
, subdural hemorrhage
Was there any history of cardiovascular disease
An autopsy can throw light on the cause of death.
A complete examination of the cardiovascular system could have shown the cause of death.
Thanks and take care
Dr Shailja P Wahal