He said the bomb, made from masking tape, batteries and a marker pen tube, must have been planted by someone else.
The businessman sobbed in court as the verdict was announced.
On 30 January, Nadeem Muhammed from Bury in Greater Manchester tried to carry a bomb onto a plane at Manchester Airport when security officers found it concealed in his case.
Nadeem Muhammad was convicted of possessing explosives with intent to endanger life at Manchester Crown Court on Tuesday after prosecutors presented evidence that he meant to detonate the device on a Boeing 737 flight to Bergamo, Italy.
Believing it was not risky, Muhammad, who had been questioned by counter-terrorism police, was released and flew to Italy five days later.
Muhammad - who was born in Pakistan but possessed an Italian passport - had denied any connection to the device in court.
Muhammad claimed in court that he had never seen the device before and that it had nothing to do with him.More news: Patriots Become First NFL Team To Buy Their Own Planes
He returned to the airport the following day to collect his mobile phone, which had been taken by police, and then again on 5 February when he boarded another flight to Italy.
He was arrested when he arrived back at Manchester Airport.
Jurors were told there was no evidence of a motive or that the incident was linked to terrorism.
Meanwhile, a thorough forensic examination of the device revealed on February 8 that it was in fact "potentially viable", and contained nitroglycerin and nitrocellulose.
He was arrested by the police upon his return to Britain on February 12. He will be sentenced at the same court on August 23.
Sue Hemming, head of the special crime and counter terrorism division in the Crown Prosecution Service (CPS), said: "Despite extensive investigation, Nadeem Muhammad's motive for attempting to take this device onto a plane remains unknown".