In response to an alarming incident of explosive depressurization on an Alaska Airlines flight, the Federal Aviation Administration (FAA) has issued a grounding order for certain Boeing 737 Max 9 aircraft. This directive has resulted in the cancellation of hundreds of flights since Saturday, with more expected as ongoing inspections take place.

The FAA directive affects a total of 171 planes operated by airlines such as Alaska Airlines and United Airlines. Inspections, which are estimated to last several days, need to be completed before the aircraft can be cleared for flight. According to the FAA, each inspection takes approximately four to eight hours per airplane.

As per tracking site FlightAware, Alaska Airlines and United Airlines have had the highest number of flight cancellations among U.S. carriers. By Monday afternoon, United had canceled over 220 flights, accounting for 8 percent of its schedule. Similarly, Alaska had canceled more than 140 flights, equivalent to 20 percent of its schedule. The majority of these cancellations were for Boeing 737 Max 9 aircraft.

United Airlines indicated that 90 flights were canceled on Saturday, with nearly 60 flights being saved by substituting them with other aircraft. The number of cancellations rose to about 180 on Sunday, with 85 flights being saved through aircraft substitutions. Additionally, Alaska Airlines announced the cancellation of around 160 flights on Saturday, impacting approximately 23,000 passengers.

While the grounding order has already caused significant disruptions, potential winter storms across the United States this week could further lead to delays and additional flight cancellations.

It is important to note that Alaska Airlines and United Airlines are the only U.S. carriers operating the Boeing 737 Max 9, while Aeromexico and Copa Airlines also utilize the Max 9 aircraft for flights to the United States. Alaska's fleet currently comprises 65 Max 9 planes, accounting for approximately one-fifth of its total fleet. United Airlines, on the other hand, operates the largest number of these aircraft, with 79 currently in service.

Both airlines have implemented measures to assist affected travelers. Alaska Airlines is offering a flexible travel policy, allowing passengers with flights through January 9 to change their reservations without any fare difference, as long as their journey is completed by January 20. Additionally, United Airlines is waiving change fees and fare differences for customers who had booked Max 9 flights on or before January 6. Eligible rescheduled flights must depart by January 18.

It is advisable for passengers to check their reservation details and seat selection maps to identify the specific aircraft they will be flying on. In case of significant delays or cancellations, travelers are entitled to refunds, and additional information can be found on the Transportation Department's dashboard.

It should be noted that the FAA directive does not affect other Boeing 737 Max operators, such as American Airlines and Southwest Airlines, as they primarily operate the smaller Boeing 737 Max 8. According to United Airlines, flights involving the Max 8 are not impacted by the grounding order.