[saiko-chriskun]

It is somewhat of a miracle. Flying stowed away on a plane is extremely dangerous and most will die, or at least come out with very serious issues.

[jessaustin]

Terrorists may not act the way you expect. Some may be perfectly willing to destroy a flight without destroying themselves. For those terrorists, the wheel well may very well come in handy as an unsecured location to stash a bomb that will be protected from the elements.