They went through the willing ones fast, then had other measures.
Which included wheeled "take-off gear" which fell off after becoming airborne and limited amounts of fuel not allowing for a round trip. There weren't many crowding to the head of the "divine wind" line.
As, apparently, opposed to those in Afghanistan and Iraq, where there seems to be more of them than targets, and a line waiting.
One can decry the morality of using this as a weapon to repel an immoral invasion, but not the effectiveness.
Arf