It is not yet clear who built the bomb but it appears to be a more sophisticated version of an underwear bomb that failed to detonate fully aboard a plane bound for Detroit on Christmas Day 2009
Authorities suspect it could be the work of master bomb maker Ibrahim Hassan al-Asiri.
Al-Asiri constructed the first underwear bomb and two others that al Qaida built into printer cartridges and shipped to the US on cargo planes in 2010.
Both of those bombs used a powerful industrial explosive and were nearly successful.
An undercover agent who foiled an al-Qaeda plot to blow up an airliner with an underwear bomb is a British national.
It seems the man who foiled al-Qaeda's latest underpants bombing plot was a Saudi intelligence agent.
Ibrahim Hassan al-Asiri is the man the FBI think is behind the latest al-Qaeda terror threat to come out of Yemen.