Airbags in aircraft - is that just a military thing?
Airbag seatbelts on planes are a "new" thing (well, since about 2001 apparently), but they're available on new-production aircraft and can be retrofitted to older General Aviation planes as well.

You can also find them on some airliners (typically in the exit rows where the next row is too far away to assume a proper brace position).

AmSafe (the folks who make a good percentage of the aviation-approved seatbelts) has a nice video (or two) on the subject of aviation airbags.