Boeing Inc. (BA) - Get Report shares bumped higher Monday as the world's biggest planemaker moved to convince the global aviation industry that software changes in the flight system of its 737 MAX series would address safety concerns clouding the aircraft following to fatal accidents over three months.

Boeing said more than 200 airline pilots, technical leaders and regulators would travel to its Renton, Washington manufacturing base Wednesday for an informational session on software and training updates for its Maneuvering Characteristics Augmentation, or MCAS, system. Meanwhile, American Airlines Group (AAL) - Get Report , the second-largest MAX 8 customer, said Sunday it would cancel around 90 flights per day and extend its truncated schedule until at least April 24 thanks to the ongoing grounding of the controversial aircraft by the Federal Aviation Administration two weeks ago.

"This is part of our ongoing effort to share more details about our plan for supporting the safe return of the 737 MAX to commercial service," Boeing said in a statement posted on its website. "We had a productive session this past Saturday and plan to reach all current and many future MAX operators and their home regulators."

"At the same time, we continue to work closely with our customers and regulators on software and training updates for the 737 MAX. Boeing is paying for the development of these updates," the statement added.

Boeing shares were marked 1% higher at the start of trading Monday to change hands at $3665.93 each, a move that would trim the stock's slide since the fatal ET 302 crash, which killed all 157 passengers on board on March 10, to around 13.5%.

That move has wiped more than $30 billion in market value from the world's biggest planemaker. American Airlines shares were seen 1% lower at $30.24 each, a move that would extend their year-to-date decline to around 7%.

Last week, Boeing faced losing a $6 billion order for the 737 MAX 8 after Indonesia's national airline moved to cancel or amend a previous agreement for the controversial aircraft in what would be the first first formal cancellation of MAX 8 deliveries that could trigger broader concerns for the back order log of nearly 5,000 units with a list value of around $600 billion.

Boeing also continues to be pressured by headlines suggesting lawmakers, federal investigators and the Department of Justice are lining up to question executives over the two horrific crashes of its 737 MAX planes that killed nearly 350 passengers and raised serious safety concerns for the flagship aircraft.

The FAA is also under scrutiny for its role in approving Boeing's MCAS , the software has been cited as the potential link between the October crash of a Lion Air flight in Indonesia and this month's Ethiopian Airlines disaster in east Africa, in 2017.

Lawmakers on the Senate's subcommittee on aviation and space are set to question FAA officials on March 27, and said Wednesday they would invite Boeing executives to face similar queries later in the spring.

"In light of the recent tragedy in Ethiopia and the subsequent grounding of the Boeing 737 Max aircraft, this hearing will examine challenges to the state of commercial aviation safety, including any specific concerns highlighted by recent accidents," the panel, which is led by Republican Senator Ted Cruz, said Wednesday, adding it would like, "in the near future, to hear from industry stakeholders that would include Boeing, other aviation manufacturers, airline pilots, and other stakeholders."

A further report, from the Seattle Times, suggests the FBI is also looking into the MAX software certification process. A Wall Street Journal report last week said the U.S. Department of Transportation is looking into the FAA's handing of the MCAS certification.