In the UK, motorcycling deaths are at 125 per billion miles (2012 figures). Assuming an average speed of 50mph, that would be about 125/(1 billion/50) = about .625 per hundred thousand hours which is at least in the same ballpark as aviation. If you allow that most planes will be going faster than a motorbike and probably have more passengers on average, they will probably come out slightly ahead.
The problem is that this figure will include people who are knowingly taking big risks (e.g. autogyro pilots at about 1 death per 1500 hours; possibly air ambulances and bush pilots who have fairly hair-raising accident rates) as well as people who are being cautious and sensible, but who get unlucky. As (IIRC Peter) pointed out, on a motorcycle however careful you are, your safety is dependent to a much greater extent on the actions of others.
Something else to like about aviation: the ratio of killed to injured people is probably higher. i.e. you’re probably less likely to end up surviving but with life-changing injuries.
To go even further off-topic, cycling would be far safer than driving, if it wasn’t for cars. Only about 1/100 cycling fatalities doesn’t involve a car.
autogyro pilots at about 1 death per 1500 hours;
Interesting! Why is that? Inherently dangerous aircraft? Poor training?
Probably a bit of both. The main problem as far as I understand it is that if ever you unload the disc, it stops spinning. This might happen if you get into a PIO or have an engine failure. There are theories that by changing the thrust-line of the engine, and adding a horizontal stabiliser, you can make them safer. There is a new generation of autogyros that are billed as being much safer, but much as I like the idea, I’m inclined to let other pilots do the test flying.
My most (financially) valuable motorcycle would sell for about 50% more than my least valuable plane :-)
Re risk, I think it is so specific to the pilot, plane and ‘mission’, and likewise for the motorcycle, that you cannot say which is safer. For me a motorcycle is probably safer on the average, or so I’d guess.
