No hijacker, whether of the crash-the-plane or hostage-exchange sort, actually wants to use their weapon. Neither running around slashing people, nor shooting o

No hijacker, whether of the crash-the-plane or hostage-exchange sort, actually wants to use their weapon. Neither running around slashing people, nor shooting off bullets in a plane. So bigger, scarier weapons are more effective at the job of creating terrified compliance. People who would rush a pocket knife may balk at rushing a machete.