Burke Lakefront Airport Commissioner Khalid Bahhur confirmed that Demjanjuk was on board a flight that left just after 7 p.m.
The deportation comes four days after the U.S. Supreme Court refused to consider Demjanjuk's request to block deportation and about 3-and-a-half years after he was last ordered deported.
Messages seeking comment were left Monday afternoon with immigration officials, Demjanjuk's son and an attorney who represents Demjanjuk in the United States.
A Berlin court on Monday rejected an appeal by Demjanjuk.
Demjanjuk, a retired autoworker who lives in suburban Cleveland, rejects the allegations against him, maintaining he was held by the Germans as a Soviet prisoner of war and was never a camp guard.
The Berlin court found that "the various losses of rights asserted by the plaintiff are solely a result of the decision of the American side to deport the plaintiff from the United States."
The administrative court rejected the argument that Germany should be compelled to withdraw its agreement to take him in, upholding a ruling issued last week by a lower court.
In a statement, it said that Germany's statement of willingness to take him in is not an "essential precondition" for his deportation to the country. Evaluating whether Demjanjuk is in a fit state to fly is a matter for American authorities alone, it added.
Demjanjuk has suffered a series of defeats in U.S. efforts to get his deportation blocked.
Once in Germany, Demjanjuk will be brought before a judge and formally charged. He will also be given the opportunity to make a statement to the court, in keeping with normal justice procedure, German Justice Ministry spokesman Ulrich Staudigl said.
Demjanjuk's family has been battling the deportation, saying he is in poor health and might not survive the trans-Atlantic journey.
Demjanjuk attorney Ulrich Busch argued last week that Germany should say it will not take Demjanjuk for humanitarian reasons. However, he conceded at the time that, even if courts decided in Demjanjuk's favor, that might not stop his deportation.
Once in Germany, Demjanjuk is expected to be held in the medical unit of a Munich prison. The government has said preparations have been made at the facility to ensure he will receive appropriate care.