It depends but the Ratio of the automobile and aircraft is huge. But plane accidents especially jetliner crashes is more like mass transit disaster but the survivability ain't that good. Having a technical problem on the air is way different to the ground and thats why having an air crash is mostly unsurvivable. By the way did you know that airsafe.com released a data for 2011 regarding air crashes.
"http://airsoc.com/articles/view/id/4f43bbe5c6f8fa0224000008/airsafe-com-safety-review-for-2011?ev=10&evp=tl"
Check the link provided.
