2006 Transatlantic Airliner Bombing Plot Successful

In August 2006, there was a plot to use liquid-fuelled bombs carried aboard flights bound from London-Heathrow to multiple US and Canadian gateways to blow them up in midair. IOTL, these terrorists were caught by British authorities just before they launched their plan.

What if they hadn't been caught, but instead, were able to smuggle their bombs (in separate parts in their cabin baggage) aboard the London-to-North America flights at Heathrow, then assemble them and activate them during the flights (either mid-ocean or on approach to their target gateway airports)? What would the damage be, and the consequences?

I was an American student studying at King's College London at the time, and made frequent transatlantic trips back and forth between my midwest US home and London, so I could have been on one of those flights if things were just a bit different.
 
Well, it would have been a catastrophe for the airline industry. Another mass disaster just 5 years after 9/11 would have killed business out of public fear and inconvenience from what would have probably been drastic security measures. It is possible that flying could have turned into a rather draconian experience.
 
I believe they wanted ten planes to go down with the attack. The casualty could would be over a thousand if most blew up, possibly even over two thousand if they all went off.
 
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