We don't know what the exact nature of this threat was but it is difficult to see why the flight was cancelled. I am not an expert, but surely the responses should be on an escalating scale.
If the threat was a potential terrorist on board - surely all passengers should have been allowed on, then screened off one by one until the terrorist was found.
If the threat was a potential bomb on board, search the plane and then allow it to leave, albeit delayed.
If it was a threat to down the plane by SAM, I think we'd have seen more activity around the airports concerned.
If the terrorists can get any flight cancelled with a phone call it gives them the power to totally disrupt our lives. Didn't it always used to be the rule that terrorist threats would not be made public as it would wreck the airline industry to be continually disrupted by false alarms?
- Michael