Anyone here have any ideas on what might have happened here. I fly a lot and its beyond me that this can happen.
Fake passports? I reckon there are several flights conducted every day on a world basis where at least one passenger has a fake passport.
No-fly lists are ineffective, those resourceful enough to be a major treat are also able to create fake identities.
Fake and stolen passports are a massive problem and not that uncommon. Most are just used by illegal immigrants etc though, not terrorists.