The terror plot involving bombs on cargo planes has investigators taking a closer look at a plane crash that happened two months ago.
A United Parcel Service flight crashed in Dubai in early September -- just one week before what authorities believe was a dry run for the bomb plot between Yemen and Chicago, Ill.
The initial investigation laid the blame on lithium batteries. Officials said that al Qaeda's targeting of cargo planes appears to be aimed at disrupting the economy.
Still, The International Air Transport Association, which represents 200 airlines, is warning governments not to overreact to Friday's bomb plot, saying "knee-jerk reactions" could harm the airline industry. The world economy, they said, is dependent on air freight.
But John S. Pistole, administrator of the U.S. Transportation Security Administration, insists world governments must also ensure security.
"We face a determined and creative enemy with innovative design and concealment of (improvised explosive devices)," Pistole said.
"We obviously have to strike a delicate balance because the flow of global commerce is key to economic recovery," he added. "Security cannot bring business to a standstill."
Meanwhile, Yemeni authorities have launched a massive manhunt for the men believed to be behind the plot.
They're searching for U.S. born cleric Anwar al-Awlaki and the 26-year-old al Qaeda operative who made the bombs.
Al Qaeda is believed to have 300 members in Yemen and U.S. military aid has been increased to $150 million a year.