Not really. The fly vs. drive decision often comes down to dollars, especially for financially stretched families. Buying 3 tickets rather than 2 might tip the financial balance toward driving.
Now if you want to argue that everyone should pay more so that kids under 2 can have a nominally free seat just like a COS, that's a different discussion.
My bad, I guess, while I agree maybe a few more families will drive if force to pay, I think its a stretch to use the death rates between the two modes of transportation as the reason why. Just nutty logic.