Frontier Airlines flight F9260, an Airbus A320, returned to land at Las Vegas-McCarran International Airport, Nevada, USA after the no.2 CFM56-5B4/P engine fan cowls separated and the reverser ("C-duct") doors opened on takeoff.
The aircraft had stayed overnight at Las Vegas and was departing on the first flight of the day. The A320 took off from runway 25R at 07:13 hours local time and landed safely on runway 26L at 07:26 hours.
This incident is one in over 40 fan cowl loss events involving Airbus A320-family aircraft since 1992. The last known incident occurred in Spain on October 25, 2018. It may, however, be the first incident where the reverser doors have opened in flight.