A Qatar Airways spokesman said package arrived in Qatar Airways' hub in Doha, Qatar on a flight from the Yemeni capital San'a. It was then shipped on a separate plane to Dubai in the United Arab Emirates, where it was discovered by authorities.
The package contained explosives hidden in a printer cartridge and was headed for the US.
Al-Qa'ida's offshoot in Yemen is suspected in the plot.
Police in Yemen have arrested a woman suspected of sending the pair of bombs powerful enough to take down aircraft.
Yesterday's arrest came as details emerged about a terrorist plot aimed at the US that exploited security gaps in the worldwide shipping system.
Investigators were hunting Yemen for more suspects tied to al-Qa'ida and several US officials identified the terrorist group's top explosives expert in Yemen as the most likely bomb-maker.
The explosives, addressed to Chicago-area synagogues, were pulled off cargo planes in the UK and the United Arab Emirates in the early hours of Friday, sparking a tense search for other devices.
It was still unclear whether the bombs, which officials said were wired to mobile phones, timers and power supplies, could have been detonated remotely while the planes were in the air, or when the packages were halfway around the world in the US.
But the fact that they made it on to planes showed that nearly a decade since the September 11 2001 attacks, terrorists continue to probe and find security vulnerabilities.
Yemen's President Ali Abdullah Saleh said the US and United Arab Emirates had provided intelligence that helped identify the woman suspected of sending the packages.
A Yemeni security official said the young woman was a medical student and that her mother also was detained.
The police action was part of a widening manhunt for suspects believed to have used forged documents and ID cards, Yemeni officials said. One member of Yemen's anti-terrorism unit said the other suspects had been linked to al-Qa'ida.
Al-Qa'ida's Yemen branch, known as al-Qa'ida in the Arabian Peninsula, said it was responsible for the failed bombing aboard a Detroit-bound airliner on Christmas Day. The bomb used in that attack contained PETN, an industrial explosive that was also used in the mail bombs found on Friday.
The suspected bomb-maker behind the Christmas Day attack, Ibrahim Hassan al-Asiri, was also the prime suspect in the mail bomb plot, several US officials said.
Al-Asiri also helped make another PETN device for a failed suicide attempt against a top Saudi counter-terrorism official last year. The official survived, but his attacker died in the blast.
Officials said the plot was discovered thanks to intelligence passed from Saudi Arabia. Without that tip, it is unclear whether anyone would have discovered the bombs before they were airborne - or on US soil.
Currently, American officials do not get details about the contents of a US-bound cargo plane until four hours before it is due to land. In the case of long distance flights, those planes would already be airborne. Once a plane lands, officials screen packages that they feel warrant a closer look.
The failed attack should be a "wake up call" that the US needed to step up security on cargo planes, said Kit Bond, the top Republican on the Senate Intelligence Committee.
The US temporarily banned all incoming cargo and mail from Yemen.
In Chicago, Rabbi Michael Zedek, the leader of a North Side synagogue said Or Chadash, a smaller congregation that uses the building, was one of the targets, but The FBI did not confirm that.
The synagogue, which has about 100 members, serves lesbian, gay, bisexual and transgendered Jews and their families.
Yemen's al-Qa'ida branch is the most active of the terrorist group's affiliates and has increasingly become the face of its recruitment efforts in the West.
The country is home to radical US-born cleric Anwar al-Awlaki, who has been linked in the Christmas Day attack and has inspired other terrorists with his violent message.
Also hiding in Yemen is Samir Khan, an American who declared himself a traitor and helps produce al-Qa'ida propaganda.
