FILE PHOTO: United Airlines planes, including Boeing 737 MAX 9 models, are pictured at William P. Hobby Airport in Houston, Texas, U.S., March 18, 2019. REUTERS/Loren Elliott

CHICAGO (Reuters) - United Airlines UAL.O is starting to move its 14 Boeing 737 MAX jets to short-term storage in Phoenix, Arizona, which has better weather for stored aircraft and where it will be easier to prepare them for commercial flight again, the carrier said on Wednesday.

Boeing Co's BA.N 737 MAX fleet was grounded worldwide in March after two fatal crashes in Indonesia and Ethiopia that killed a total of 346 people within five months.

The aircraft maker is working on a fix for the software at the center of both crashes and is aiming to get the jet back in the air as soon as October, Boeing Chief Executive Dennis Muilenburg told Reuters on Tuesday.

Once the U.S. Federal Aviation Administration approves the new software and pilot training, airlines will have to upload the software changes and run a series of maintenance checks on the jets before flying them again with passengers.

Having all of its MAX planes in one place at Phoenix Goodyear Airport will be more efficient for that process, United said.

The airline has received a ferry permit from the U.S. Federal Aviation Administration for each of the 14 flights to Phoenix from their current locations in Houston, where it cited hurricane threats, and Los Angeles. The permits allow an airline to ferry an aircraft from one place to another.

Airlines that own the MAX have been forced to cancel thousands of flights since the planes were grounded, hitting profits during the busy summer travel season.

Chicago-based United has removed its MAX jets from its flight schedule until Nov. 3, and did not make any changes to that timeline on Wednesday.

Southwest Airlines LUV.N, the world's largest MAX operator, is scheduling without its 34 jets until early January. Those jets are parked at a facility in Victorville, California, at the southwestern edge of the Mojave Desert.