American Airlines is extending a cancellation of flights aboard any Boeing 737 Max aircrafts in its fleet until August, the company said in a letter to its employees.

In the letter, American Airlines CEO Doug Parker and President Robert Isom said that they believed the aircraft would be re-certified before August, but added that removing the planes until then would allow them to better plan for the busy summer travel season.

"Once the MAX is re-certified, we anticipate bringing our MAX aircraft back on line as spares to supplement our operation as needed during the summer," the letter states.

American Airlines estimates that the cancellations will affect approximately 115 flights per day — or 1.5 percent of the company's total flying each day through August 19.

"We remain confident that the impending software updates, along with the new training elements Boeing is developing for the MAX, will lead to recertification of the aircraft soon," the letter states.

This is the latest extension of the 737 Max cancellations for American Airlines. In March, the company said it would extend its cancellations through April 24.

The airline is not the first to cancel its flights on the 737 Max through August.

Southwest Airlines said it would also be removing flights with the 737 Max aircraft from its schedule through Aug. 5.

President Donald Trump announced an emergency order from the Federal Aviation Administration, which grounded Boeing 737 Max jets in the wake of an Ethiopian Airlines crash and a Lion Air accident in October that together killed 346 people.