Amidst the buzz that grounded Boeing 737 aircraft’s return to service by October, the mystery persists why leading airlines including American Airlines and United Airlines have extended cancellations of flights on the 737 Max until December 3.

It shows two underlying reasons—one is the likely delay in returning to service or it can be the plan for a wait and watch approach.

Some media reports also suggested the 737 max jets may stay grounded even during the holiday season citing technical delays.

According to Boeing news, by the early fourth quarter, the troubled jet was to be back in skies. This followed reports of a certification flight by the Federal Aviation Administration (FAA) and vetting of the upgraded flight control software MCAX by leading regulators.

In September, the 737 Max grounding enters the sixth month. The grounding of Max jets followed two major crashes with no survivors.

The Lion Air Flight crashed in October 2018 off the coast of Indonesia and Ethiopian Airlines Flight in March outside Addis Ababa. Together 346 people were killed.

American leads cancellation of 737 oriented flights

American Airlines previously canceled 115 daily flights on the aircraft through November 2.

In the latest round of cancellations, 140 American Airlines flights per day will be canceled.

According to American, it announced cancellations well in advance so that AAL has enough time to assign new aircraft to 737 Max routes or rebook customers whose flights had been canceled.

American Airlines assured customers that canceled flights can be rebooked or a refund will be offered.

American Airlines in August became the first US airline to cancel a route because of the grounding.

The largest airline in the world canceled daily flights from Oakland to Dallas and back because it wanted to deploy the plane flying that route for other busy routes.

The United Airlines on Friday said it would cancel 90 flights until December 19 due to the 737 Max issue.

Southwest has the largest fleet of 737 Max planes than any other U.S. airline. The airline said it would be canceling 180 daily flights until January 5.

In addition to Southwest Airlines, Air Canada also decided not to fly Max flights through early January.

Delay likely even after software approval

Boeing has been hoping to a return to service “that begins early in the fourth quarter.”

The aircraft manufacturer was also working on a software fix for the plane and is readying submit the same to the Federal Aviation Administration (FAA) by October expecting the plane to be certified this fall.

GettyImages-Boeing test flight
A Boeing 737 MAX 8 airliner lifts off for its first flight on January 29, 2016, in Renton, Washington. Photo by Stephen Brashear/Getty Images

Boeing also worked on a revamp to enable Max’s flight control system to compare data from two onboard computers instead of one.

However, some reports suggest the return of 737 may be delayed because the FAA may ask for more measures on pilot training.

According to a report by the Wall Street Journal, there was friction at a meeting in August when Boeing met regulators from the U.S., Europe, Brazil and elsewhere.

Adding to the concern was surveys among air travelers that showed the “fear factor” in flying 737 Max 8 exists.

According to one survey, 20 percent of U.S. travelers would try to avoid the plane in the first six months even it resumes service, said a study led by consultant Henry Harteveldt.

A UBS Group AG survey said 70percent air travelers are reluctant to book a flight on the Max.

Boeing has already faced the brunt of the 737 jet fallout. The Boeing stock has been down 21 percent in the five months since March and losses keep mounting from the grounded fleet.