Six months after the FAA grounded the Boeing 737 MAX aircraft, scores of the planes continue to sit idle across the country.

And despite the amount of media attention surrounding the MAX planes, the timeline for when they will return to service remains uncertain. What is certain is that US airlines aren’t counting on their return in the near future.

A near-constant topic in aviation news, the MAX 8 grounding was a direct result of two fatal crashes involving the jet aircraft in October 2018 and March 2019.

The only domestic airlines with Boeing 737 MAX aircraft in their fleets – United Airlines, American and Southwest – continue to make schedule adjustments that exclude use of the MAX through as late as January.

In September, American Airlines announced it was extending flight cancellations due to the MAX 8 grounding through Dec. 3. Airline officials stated that approximately 140 daily flights will be canceled during that timeframe.

“American Airlines remains confident that impending software updates to the Boeing 737 MAX, along with the new training elements Boeing is developing in coordination with our union partners, will lead to recertification of the aircraft this year,” the airline said.

In an earnings report on its website in late July, Southwest noted that it expects its MAX fleet will return to service sometime during the last quarter of 2019, based on information provided by Boeing. Southwest’s grounded Max 8s remain at an airport in Victorville, California.

“The FAA will determine the timing of MAX return to service, and we offer no assurances that our current assumptions and timelines are correct,” Southwest CEO Gary Kelly stated. “The vast majority of our customers’ itineraries have been unaffected by the MAX groundings, and I commend our people for their extraordinary efforts to minimize disruption to our operations.”

The latest statement on Boeing’s website regarding the MAX was released in June. It revealed the discovery of another software update that must be made before the company can assess whether the aircraft is ready for test flights as a first step toward eventually resuming commercial operations.

“Boeing will not offer the 737 MAX for certification by the FAA until we have satisfied all requirements for certification of the MAX and its safe return to service,” the company said.

As airlines prepare to address customer concerns for flying on the aircraft when it returns to service, United has announced it will allow passengers to rebook their flights on another plane, at no additional cost. Similarly, a recent article on CNN.com reported that Southwest will offer “full flexibility” for passengers to rebook on another aircraft. American Airlines has not yet determined its policy for customers that don’t want to fly the MAX.

Another CNN report this week mentioned that other regulatory agencies worldwide may not follow the FAA’s schedule for resuming MAX flights. This “phased un-grounding” could see the aircraft flying in other countries sooner than the U.S.

At Pittsburgh International Airport, Southwest Airlines was the only carrier to operate flights on MAX 8 aircraft. At the time of the grounding, American did not operate any flights to and from PIT using the MAX 8, and less than 1 percent of Southwest flights to and from PIT in February were aboard MAX 8s.

United Airlines, which has 737 MAX 9 aircraft in its fleet, did not operate any flights on the aircraft for routes in and out of Pittsburgh International.