I sort of agree. There is some cost-safety trade-off curve, and it's almost certainly true that you can get more safety for less cost/hassle on airplanes (or any large-group travel) than private cars. So in that sense, yes, the optimal amount of safety will be higher for planes.

However, I think we should still respect individual preferences for safety in the sense that public transit should try and make the trade-offs individuals would make according to their values. In practice that means trying to estimate the value individuals put on safety through their revealed preferences, with cars being a key example. Although there are some choices the FAA makes here that a smart, on some other choices I think they impose hassles on passengers that aren't remotely justified by the safety benefit, e.g., mandatory seat belt use.