As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ONT - FLT 1660 - EN ROUTE AFTER TAKEOFF, FLIGHT ATTENDANT NOTICED SMOKE AND FUMES IN CABIN. COCKPIT CONFIRMED FUMES SMELL IN COCKPIT. RETURNED AND LANDED ONT WITHOUT INCIDENT. PERFORMED PACK BURN ACCORDING TO MM. NO ODOR DETECTED. SYSTEM GROUND CHECKED, NORMAL OPERATION. (X)