Bomber Germaine Lindsay was born in Jamaica
A website that can log use of flight simulators has said it does not believe the "Jermaine Lindsay" in its records is the 7 July bomber of the same name.
Simairline.net recorded five flights by a Mr Lindsay between December 2003 and March 2004.
Germaine Lindsay, 19, of Aylesbury, Bucks, detonated the bomb near King's Cross killing himself and 26 others.
But Simairline.net says it does "not believe that there is any connection between these two individuals".
A statement said it had "been informed by one of its press contacts that our former member is most likely a different individual from the one involved in the attack on London's Piccadilly Line".
The company said it had "limited and unconfirmable knowledge" of its users, and that its Mr Lindsay had been a UK resident who listed Heathrow as his nearest commercial airport.
He lost his membership on 1 May 2004 after submitting no flight reports the previous month, Simairline.net said.
The 9/11 Commission in the US last year concluded that those responsible for flying the planes into the World Trade Center and Pentagon had used PC-based flight simulators for training.
The Simairline.net statement pointed out that it "does not provide flight instruction to its members".
"Simairline.net provides information about airlines and free add-on software for Microsoft Flight Simulator," it said.
Simairline.net's hundreds of members use the site to access accurate flight schedules when using flight simulators.
"Flight training is an expensive and time-consuming process that can not be learned through a computer; it must be undertaken with an instructor in real life," the statement added.
The company said it was working with the Metropolitan Police to establish whether its former member was the bomber, whose name has been spelt both Germaine and Jermaine.