CATHAL FLYNN: The failure was on my part to put together certain straws in the wind: That people are suicidal, that people can learn how to fly planes, and that people who next took over planes might not be taking it over to divert it, but might want to use it as a missile
TOM BEARDEN: But no one predicted that.
CATHAL FLYNN: No one predicted that. But I'll regret it. I do regret it. (Source)