More people die in bed than in aeroplanes or on motor-bikes.
If we spent as long flying as we do in bed (8 hours a day) then the overwhelming majority of us would die flying. Well over 90% assuming you start when you're 20 and carry on until you're 80.
OK, perhaps it would be slightly less than that because the bold pilots would all die young and the less bold pilots would benefit from their great wealth of experience to fly better and safer than they do now. However, at the current rates, flying is way more dangerous per hour than sleeping, and way more dangerous per mile than driving.
The other difference is that most people who die in their sleep are almost always reasonably old. People who die flying are almost by definition healthy and active, often with dependants. It's a very different thing for your heart to stop whilst you're asleep in bed aged 80, or to auger in aged 30 leaving small kids behind.