On October 21, 2009, one of the strangest aviation incidents occurred. A regularly scheduled Airbus A320 flight on Northwest Airlines Flight 188 landed over one hour late at Minneapolis-St. Paul (MSP), after flying from San Diego. However, the delay was not caused by a mechanical problem or weather. The plane landed late simply because the pilots forgot to land the plane. 

The pilots completely phased out during the flight and overshot the Minneapolis area by 150 nautical miles. Though the aircraft landed safely in Minneapolis and taxied normally to a gate with no injuries involved to passengers, the situation could have been far worse. 

Around two hours into the flight, as the aircraft passed through Denver, Colorado, it lost contact with Denver Air Traffic Control (ATC). As a response, Denver ATC tried to get the plane to gain contact with Minneapolis ATC but failed. Even texts from Northwest and alerts from other aircraft were unsuccessful at regaining contact with the plane. The situation got so problematic that even the White House Situation Room officials were alerted. 

Just as fighter jets were mobilizing to check on the plane's status, Minneapolis ATC regained contact with the plane, although, by that point, the aircraft was over 100 miles east of the airport in Eau Claire, Wisconsin. At that point, the pilots were in full contact with ATC and returned to Minneapolis to land, but not after having to fly in ATC-instructed patterns to confirm that the pilots had control of the aircraft. 

Surprisingly, the pilots told investigators they were not asleep at the yoke but had been reviewing schedules on their laptops. Still, reviewing schedules on laptops is a serious breach of airline policy and resulted in the pilots' grounding on October 27, 2009. The pilots also reported not hearing any alerts or messages in the cockpit outside of Captain Timothy Cheney hearing "chatter" on the radio, according to his interview with investigators. 

A secondhand account of the situation by a friend of Captain Cheney states that the First Officer had, while Captain Cheney was in the bathroom, switched the frequency as instructed but had flubbed some numbers such that the aircraft was tuned to Winnipeg, Manitoba airspace where any communication between the center and the plane would be inaudible given the distance. 

Other factors, such as the Airbus A320 not featuring advanced technology to use an audible chime to alert the crew of messages from the airline, contributed to a lack of situational awareness that was only resolved when flight attendants asked for an update on landing time at MSP. 

In the end, nobody was hurt in the incident, and to a degree, the incident is less serious than many might suspect. We cannot be 100% sure of the events that transpired, and indeed, not all of the conversation history from the cockpit of that flight is available to investigate. Still, the incident did prompt serious changes in the industry. Lawmakers moved to ban laptops in the cockpit, a policy some airlines have adopted, and additional automation procedures have been implemented. This type of incident, fortunately, has not occurred since.