The medical examiner's office in Chicago said the process to identify the remains could take days.
The plane had 52 passengers and six crew onboard. No injuries were reported.
The couple were opening a site in Chicago, which the former president described as a "celebration of community".
The former US president urged unity at a star-studded dedication ceremony in Chicago.
As the delivery vehicles increasing take to US streets, bans and protest groups are springing up.
Traci Quinn, who was jailed for a drugs offence, has transformed herself and set up a successful firm.
The family of the late US civil rights activist met thousands of mourners who came to the Rainbow PUSH Headquarters in Chicago to pay their respects.
The BBC's Gary O'Donoghue spoke with city residents about what the civil rights leader's passing means for the community shaped by his activism.
Businesses in Little Village - known as the "Mexico of the Midwest" - are suffering after weeks of immigration raids.
