A Seattle-bound Alaska Airlines flight from Chicago was diverted to Minneapolis-St. Paul after the crew reported odor in the cabin on Wednesday evening.
As a precaution, Flight 51 landed at Minneapolis-St. Paul International Airport at 7:17 p.m. local time.
Airport spokesman Patrick Hogan told The Associated Press on Thursday that the smell was similar to that of burnt plastic. The source had not been identified.
Six crew members received medical evaluation at the airport and four were transported to the hospital for further evaluation. Two of the 144 passengers were evaluated at the airport. Some people reported having trouble breathing, Hogan said.
The flight was canceled and passengers were re-booked on a different flight to Seattle.
The cause of the odor is being investigated and the plane has been removed from service pending an inspection.