First of all, Harry Brown would have allowed the passengers and pilots to have been able to defend themselves, thus foiling any hijacking attempt, much like the way things were prior to the 1970's, when no americans ever lost a life in the one or 2 very rare ariline hijackings from 1914-1970's.
Furthermore, a libertarian government would not have bombed at least one country each and every year somewhere in the world, year after year, making many enemies bent on revenge.
Lastly, Harry Brown long ago called for assassination of people like bin laden, who are guilty of terrorist activities that kill americans, so this entire incident of yesterdays bombings would be hypothetical anyway, as bin laden would be long dead by now, and the World Trade Center buildings would still be there.
If you followed the link, or went to his site, here you know it was published yesterday. He is truely an ideologue, limited by his rhetoric.
Like anything written by a politician, there is some truth in it. But I'd have to say that it doesn't predominate or shine through and shows his limitations and those of his party.