question: Why do airlines wait so long to notify passengers of delayed or cancelled flights when they know the necessary plane hasn’t taken off from its prior point of origin yet?
comment: They might be able to use a different plane. Until the actual delay is known and other avenues of delay-reduction are applied, it would be a waste to tell customers there has been a delay because in the end, there might not be. Plus, people should be at the airport early for their flight, which often means by the time a delay is confirmed the passengers will already be at the airport. Since they shouldn't try leaving and coming back in case the delay is lessened while they are gone, it makes little difference how early they are notified of a delay.
passages: BULLET::::- A glitch in the iPad application FliteDeck – used by American Airlines pilots to view flight plans – that causes the application to display duplicate charts for Ronald Reagan Washington National Airport in Arlington, Virginia, and stop functioning forces American to ground dozens of flights. Groundings and delays continue into 29 April before the airline resolves the problem.
  
  Section::::Events.:May.
  
  BULLET::::- 1 May
   Several airports, such as Midway International Airport and O'Hare International Airport, have occasionally notified flyers that they should arrive around 3 hours before their flight, in case delays are to occur due to the supposed inefficiency of the TSA.
  
  Periodically, flyers have even missed their flights as a result of long lines for screening and other general delays, which has influenced people to want to switch to private screening agencies.
   As non-U.S. countries and airlines began grounding the 737 MAX, Boeing stated: "at this point, based on the information available, we do not have any basis to issue new guidance to operators." Boeing said "in light of" the Ethiopian Airlines crash, the company would postpone the scheduled March 13 public roll-out ceremony for the first completed Boeing 777X.
   EDCT and expect further delays.
  
  When conditions improve, or when demand decreases, the ATCSCC begins running compressions. This is when the ATC facility can accept more traffic or users; that is, airlines cancel flight plans, thus causing openings. This causes other EDCT times to change and decrease delays.
   BULLET::::- In violation of U.S. Federal Aviation Administration rules, American Airlines mistakenly flies an Airbus A321S, a version of the Airbus A321 that is not ETOPS-certified for long flights over water, from Los Angeles, California, to Hawaii, not discovering the error until the airliner had made half the flight. The plane completes the flight to Hawaii, then returns empty to Los Angeles. The airline makes computer software changes that it says will prevent future mix-ups between the A321S and Ameerican's fleet of ETOPS-certified A321H airliners.
  
  Section::::Events.:September.
   For efficiency of operations, some ATC operations will routinely provide "pop-up" IFR clearances for aircraft operating VFR, but that are arriving at an airport that does not meet VMC requirements. For example, in the United States, California's Oakland (KOAK), Monterey (KMRY) and Santa Ana (KSNA) airports routinely grant temporary IFR clearance when a low coastal overcast forces instrument approaches, while the rest of the state is still under visual flight rules. 
   Part of flight planning often involves the identification of one or more airports which can be flown to in case of unexpected conditions (such as weather) at the destination airport. The planning process must be careful to include only alternate airports which can be reached with the anticipated fuel load and total aircraft weight and that have capabilities necessary to handle the type of aircraft being flown.
   By the end of July, the software amendment was expected be submitted to the authorities in October, not September as previously indicated.
  
  Section::::Return to service.:Boeing.
  
  Boeing initially hoped that flights could resume by July 2019; by June 3, CEO Dennis Muilenburg, expected to have the planes flying by the end of 2019 but declined to provide a timeline.
  
  On July 18, Boeing hoped to return the MAX to flight during the fourth quarter of 2019, but indicated that this was its best estimate and that the date could still slip.
  
  Section::::Return to service.:Airline projections.
   BULLET::::- The United States Department of Justice files legal papers in federal court in Portland, Oregon, stating that passengers denied boarding on an airliner will receive a letter telling them that they are on the secret No-Fly List and providing them with the option of requesting additional information – which the United States Government will provide if sufficient unclassified information is available for an answer – as well as of submitting information with which to challenge their inclusion on the list. Previously, travelers denied boarding could appeal their denial of boarding to the United States Department of Homeland Security, but were not told whether or not they were on the No-Fly List, a procedure a federal judge had ruled unconstitutional in June 2014. About 47,000 people are on the No-Fly List; about 800 of them are Americans.
   In efforts to prevent incidents such as the disappearance of Malaysia Airlines Flight MH370, a new standard has been issued for all commercial aircraft to report their position every 15 minutes to air traffic controllers regardless of the country of origin. The regulation was taken into effect in 2016 by the ICAO, and requires no new aircraft equipment so long as airlines adhere to it. This requirement is part of a long-term plan, in which by 2020 ICAO will require new aircraft be fitted with data broadcast systems that air traffic controllers are in constant contact with. The plan is called the Global Aeronautical Distress and Safety System.
   BULLET::::- Allegiant Air Flight 426, a McDonnell Douglas MD-80 with 144 people on board flying from McCarran International Airport in Las Vegas, Nevada, arrives over its destination, Hector International Airport in Fargo, North Dakota, low on fuel and finds the airport temporarily closed for training by the United States Navy Blue Angels flight demonstration squadron. After a discussion between the pilot and tower about how Allegiant Air should have known about the closure and options for Flight 426 to circle or divert to another airport, the Allegiant Air pilot announces that he has insufficient fuel for either option, declares a fuel emergency, and lands safely at Hector International.
   BULLET::::- A volcanic eruption in Tonga sends ash into the sky, prompting the cancellation of all international flights to and from the country. Flights do not resume until 14 January.
  
  BULLET::::- Divers retrieve the flight data recorder from Indonesia AirAsia Flight 8501s wreckage on the bottom of the Java Sea.
  
  BULLET::::- 13 January
  
  BULLET::::- Divers retrieve the cockpit voice recorder from Indonesia AirAsia Flight 8501s wreckage on the bottom of the Java Sea.
  
  BULLET::::- 14 January
   Section::::Reactions.:International agencies.
  
  In a May 22 statement, the European Aviation Safety Agency (EASA) reaffirmed the need to independently certify the 737 MAX software and pilot training.
  
  The International Civil Aviation Organization (ICAO) invited global regulators "to review pilot licensing requirements". It is the first time ICAO will undertake such a broad review.
  
  The meeting was scheduled before the crashes and could extend beyond the requirements for commercial pilots, according to Miguel Marin, chief of the operational safety section of ICAO's Air Navigation Bureau.
  
  Section::::Reactions.:Industry experts.
   BULLET::::- To deter Europeans from travelling to fight for the Islamic State or returning to Europe from the Middle East to conduct terrorist attacks in Europe, the European Parliament passes the "Passenger Name Record" proposal requiring airlines to transfer passenger data such as seat numbers and payment information to law enforcement authorities for flights into and out of the European Union. The proposal must undergo a further period of negotiation with the governments of individual European Union member countries before becoming law.
   Textron-owned simulator maker TRU Simulation + Training anticipates a transition course but not mandatory simulator sessions in minimum standards being developed by Boeing and the FAA.
  
  On July 24, Boeing indicated that some regulatory agencies may mandate simulator training before return to service, and also expected some airlines to require simulator sessions even if these are not mandated.
  
  Section::::Return to service.
  
  Section::::Return to service.:Aviation authorities.
   Flight plans may be submitted before departure or even after the aircraft is in the air. However flight plans may be submitted up to 24 hours in advance either by voice or by data link; though they are usually filled out or submitted just several hours before departure. The minimum recommended time is 1 hour before departure for domestic flights, and up to three hours before international flights. This time depends on the country the aircraft is flying out of.
  
  Section::::Other flight planning considerations.
   BULLET::::- Argentina: The National Civil Aviation Administration (ANAC) closed airspace to Boeing 737 MAX flights.
  
  Section::::Groundings.:Airlines.
  
  After the Ethiopian Airlines crash, some airlines proactively grounded their fleets and regulatory bodies grounded the others. (This list includes MAX aircraft that have powered on their transponders, but may not yet have been delivered to an airline. Some pre-delivered aircraft are located at Boeing Field, Renton Municipal Airport and Paine Field airports).
  
  Section::::Analysis.
   ETOPS-240 and beyond are now permitted on a case-by-case basis, with regulatory bodies in nations ranging from the US, to Australia, to New Zealand adopting said regulatory extension. Authority is only granted to operators of two-engine airplanes between specific city pairs. The certificate holder must have been operating at 180-minute or greater ETOPS authority for at least 24 consecutive months, of which at least 12 consecutive months must be at 240-minute ETOPS authority with the airplane-engine combination in the application.
   Flight delays are an inconvenience to passengers. A delayed flight can be costly to passengers by making them late to their personal scheduled events and commitments. A passenger who is delayed on a multi-plane trip could miss a connecting flight. Anger, frustration and even Air rage can occur in delayed passengers.
  
  Section::::Flight delay data in the USA.
  
  Section::::Flight delay data in the USA.:Yearly data analysis.
   The DHS Traveler Redress Inquiry Program (TRIP) is a procedure for travelers who are delayed or denied boarding of an aircraft, consistently receive excess scrutiny at security checkpoints, or are denied entry to the U.S. because they are believed to be or are told that they are on a government watch list. The traveler must complete an online application at the Department of Homeland Security website, print and sign the application, and then submit it with copies of several identifying documents. After reviewing their records, DHS notifies the traveler that if any corrections of data about them were warranted, they will be made.
   On , Indonesian Ministry of Transport representative Djoko Murjatmojo stated that "officials at the airport operator in Surabaya and [the] air traffic control agency who had allowed the flight to take off had been moved to other duties", and an immediate air transport directive had been issued "making it mandatory for pilots to go through a face-to-face briefing by an airline flight operations officer on weather conditions and other operational issues prior to every flight".
   BULLET::::- A computer automation problem grounds 150 United Airlines flights – about eight percent of United's morning schedule – nationwide in the United States for about 40 minutes until the airline can ensure that all flights depart with proper dispatching information.
  
  BULLET::::- Landing his de Havilland Canada DHC-1 Chipmunk at Pearson International Airport in Toronto, Ontario, Canada, retired de Havilland Canada test pilot George Neal sets the world record for oldest active licensed pilot at the age of 96 years 194 days. Neal had held a Canadian pilot's license since 1936 and flown 15,000 hours on 150 different aircraft types.
   BULLET::::- Europe: The European Union Aviation Safety Agency (EASA) suspended all flight operations of all 737-8 MAX and 737-9 MAX in Europe. In addition, EASA published a Safety Directive, effective as of 19:00 UTC, suspending all commercial flights performed by third-country operators into, within or out of the EU of the above mentioned models
  
  BULLET::::- Canada: Minister of Transport Marc Garneau said it was premature to consider groundings and that, "If I had to fly somewhere on that type of aircraft today, I would."
  
  BULLET::::- Australia: The Civil Aviation Safety Authority banned Boeing 737 MAX from Australian airspace.
   Airline and aircraft safety inspectors, on the other hand, were deemed nonessential and furloughed. A news report on January 12, 2019 stated that the Federal Aviation Administration had returned 500 furloughed safety inspectors back to work and would return more to work in the following weeks.
  
  As the airline and aircraft safety inspectors were furloughed, the certification process of the Airbus A220 in the US was stalled. Delta Air Lines was forced to delay the launch of the new aircraft, and to use other models of aircraft to serve those routes that was supposed to be served with A220.
   On June 11, Norwegian Flight DY8922 attempted a ferry flight from Malaga, Spain to Stockholm, Sweden. Such flights can only be flown by pilots meeting a certain EASA qualification, and with no other cabin crew or passengers. The flight plan contained specific parameters to avoid MCAS intervention, flying at lower altitude than normal with flaps extended, and autopilot on. However, the aircraft was refused entry into German airspace, and diverted to Châlons Vatry, France, where it remains until an alternate flight plan is available.
  
  Section::::Groundings.:Regulators.
  
presuppositions: Airlines withhold information about delays and cancellations.  Airlines only use planes that are scheduled to fly from their point of origin.
corrections: Airlines aren't withholding information, they are trying their best to find another option before resorting to cancels or delays.  Airlines sometimes use different planes from those that are scheduled to fly from their point of origin.
raw_presuppositions: Airlines withhold information about delays and cancellations.  Airlines only use planes that are scheduled to fly from their point of origin.
raw_corrections: Airlines aren't withholding information, they are trying their best to find another option before resorting to cancels or delays.  Airlines sometimes use different planes from those that are scheduled to fly from their point of origin.