With enough money, you can buy bastards that will do anything for your cause. No point profiling when you have to deal with such mercenaries; although it doesn't hurt to be extra cautious when loading planes with people of middle eastern backgrounds does it?

My prediction is that terrorists will resort to targeting passenger ships, and much easier tourist targets in Europe and North America. Unfortunately, they will find these much easier to score; and will probably do it with an avenue of escape in mind, not having to die during the process.