That's what I was saying: a frangible bullet will not pass through the thin skin of an airplane, so how can you expect it to pass through a leather jacket?
Expanding bullets are nowhere as eficient at passing through clothing without distortion as a solid swc.
If you had read Elmer Keith's books, you would know that this kind of debate has been going on since black powder shooters went from round balls to swc shapes.
You would be astounded at the latest forensic technology for linking a particular firearm to a spent bullet. It is no longer a matter of only rifling marks on the projectile.
And, finally, since there has not been a shooting with the current crop of frangible bullets, nobody can do anything but speculate what could happen in the way of terminal ballistics. If you recall the garbage that was printed when Glaser safety slugs first showed up on the market...most of which was later proven to be wishful thinking, you will get my point.
What the Air Marshals use in their pistols isn't much of a selling point; they used to load up with full wadcutters, and if some folks had their way, they would use rubber bullets.
Expanding bullets usually don't expand; they hit something solid and distort.
So, what is the perfect self-defense load? No definitive answer, we are ALL still testing and trying everything new that comes onto the market. Therefore, the amount of testing we have done and the results prejudice out thinking, so all of us have different ideas and hopes that our theories will work out for the best.
In that respect, the jury is still out...on my theories as well as yours.