[thinking]

Deep Vein Thrombosis, blood clots in the legs caused by sitting too long, like in air travel....

[CholeraJoe]

Easily detected at autopsy and not mentioned.

[RedRightReturn]

Agree Joe...DVT usually only occurs after prolonged periods of sitting idly. PHL to Tampa is a relatively short hop, no time for DVT to set. It certainly would have been detected in the heart, lungs, or brain and quickly ruled as the cause of death.