Did the world change yesterday? From America's standpoint, it certainly has. It can no longer feel comfy & isolated - there is a real world out there beyond its borders. Since the fall of the Berlin Wall, America has had essentially global - and possibly benevolent - hegemony; its political weight and responsability is unparalleled. The pentagon is a military and thus legitimate target for whom believes that they are in serious conflict with American policy. The WTC was a symbol (it is the one that got most coverage), but also a civilian target, and is thus inexcusable. Combining the two was a huge error for it entices all too easily immediate reactions of anger and hate.
Did the acts require immense amounts of ressources, as most observers note? The opposite may be true. The most difficult part was to get the right pilots to do the job - 4 to 8 individuals and their trainers. The other part of the equation is time: time to observe the behaviour at airports - security measures and logistics; would that require a crew of 200? Doubtful. It appears very plausible that a small, dedicated group could evade the CIA, NSA and FBI nets; this is consistent with guerilla warfare tactics of small mobile units that are difficult to track down, create significant damage and make the ennemy unsure of itself (has America forgotten Vietnam). For this was an act of guerilla warfare.
The main ressource was serious planning: the flights were early morning long-distance; security personnel are naturally less alert at that time of day, the flights are least likely to withstand delays and are full of fuel for maximum destructive effect. At best, the number of flights involved was calculated for a 'portfolio effect'; some would fail while others would succeed with a devastating net effect on public opinion. The planners are no fools.
Do we have a guilty party? No. Not so fast. If due process is part of the American judicial way of life, why should this be dropped in the face of any event? Everyone, in particular the media, is pointing the finger in one direction. They may be correct, but get evidence first, one may learn something. This haste in finding the culprit smells of manipulation. Recall: it is quite possible that this attack was organised by relatively small units...
Do we know how to react? Probably not. The shock and emotion is too high. A bit of time is necessary to be able to deal effectively with this situation.