The MD83 jet -- adorned with Romney's campaign slogan, "Believe in America," and its web address, Mittromney.com, is parked at Willow Run Airport in Van Buren Township, the Detroit Free Press reported.
The plane, along with a DC9 used by Romney's running mate, U.S. Rep. Paul Ryan of Wisconsin, were leased from Michigan-based USA Jet, a cargo company that also leases private planes.
"We did fly the governor ... and Congressman Ryan during the campaign," company Chief Executive Officer David Schembri said. "It was specific to the campaign and they were returned here."
Schembri said the planes will return to regular business now that the campaign is over.