A senior Pakistani intelligence official told ABCNews.com his death cannot be officially confirmed until the results of DNA tests are known because the bodies were burned beyond recognition in the attack.
But the official said the U.S. believes it is certain Rauf was killed.
There was no formal comment from U.S. but one senior U.S. official said "there is good reason to believe this guy is no longer around."
Rauf is believed to have been the major link between British al Qaeda cells and the terror network's headquarters in Pakistan.
He was arrested in Pakistan following the disruption of the plot but later escaped from custody under mysterious circumstances in December of last year.
The airline bomb plot would have been the most catastrophic attack by al Qaeda since the 9/11 attacks if it had been carried out, according to CIA director Gen. Michael Hayden.
It was Rauf's arrest in Pakistan in August 2006 that led police in Great Britain to call off a surveillance operation and to swoop in on an alleged al Qaeda cell whose members were said to be well-advanced with preparations for a potentially deadly operation to use liquid bombs on airplanes, which could have killed hundreds if successful.
According to British press reports, U.K. prosecutors said that the target aircrafts were destined for six American and Canadian cities: New York, Washington, Chicago, San Francisco, Toronto and Montreal.
The public revelation of the alleged plot led to unprecedented new security measures at airports worldwide, most of which remain in force.
Three British citizens were convicted in Septemer of conspiracy to commit murder, but the overall outcome of the trial was disappointing for British authorities who had put eight men on trial and failed to secure a verdict on four of them. One man was cleared of all charges. Prosecutors say they are seeking a retrial of the other seven defendants.
The missile strike today was the 25th such attack since August in a U.S. offensive that has killed more than a half dozen top al Quaeda leaders in the tribal areas of Pakistan where the terror group has established what had once been a safe haven.