The Japanese use of Kamikazes in World War 2 didn't run into this problem because the war didn't last long enough, and they found that they could build planes (and boats, and subs) faster than they could adequately train pilots. Training adequate pilots is a major stumbling blocks, and regardless of what illusions of silliness the 911 perpetrators were under, the requirements of training necessitate that you learn how to land.
Carrying around a bomb strapped to yourself requires very little skill. So obviously you could run out of people much faster. The "War on Terror" or maybe they would call it "The War on the Great Satin" has been going on long enough to tap supplies.
Asher Zeiger, Times of Israel, 14 August 2012 (hat tip: NC)
Apparently low on bombers, al-Qaeda is running a (short-term) employment advertisement on its Shumukh al-Islam Internet forum. Under the heading “Area of activity: The planet Earth,” the ad seeks jihadists to carry out suicide attacks.
Applicants must be Muslim, mentally mature, dedicated, able to listen, and utterly committed to completing their mission, the Hebrew daily Yedioth Ahronoth reported on Tuesday…
No, you wouldn't want to get caught.The job description promises only a “very slight chance of being caught.”