Update: Market Chatter: Boeing Discovers Software Glitch on 737 MAX Planes That Could Affect Landings

08:57 AM EDT, 09/28/2026 (MT Newswires) -- (Updates with United Airlines' response in the fifth paragraph and Boeing's latest stock moves in the seventh paragraph.) Boeing (BA) has discovered a software glitch in its 737 MAX planes that could cause navigation system failures and raise safety concerns during landings, The Wall Street Journal reported Monday, citing a document it examined. The glitch takes place during cockpit software updates, which occur when planes change their flight paths after a missed approach and could force pilots to fly manually, the report said. Boeing, airlines, and the Federal Aviation Administration, or FAA, are assessing the issue, the Journal reported. Southwest Airlines (LUV) and United Airlines (UAL) have informed Boeing they don't want new planes with the flawed software and have requested an earlier software version, the report said, citing industry officials. United said in an email to MT Newswires that it does not currently have any 737s operating with the new software and is not taking deliveries of new aircraft with the software. Boeing, Southwest, and the FAA did not immediately reply to MT Newswires' request for comment. Shares of Boeing were down 2.5% in Monday's premarket trading. (Market Chatter news is derived from conversations with market professionals globally. This information is believed to be from reliable sources but may include rumor and speculation. Accuracy is not guaranteed.)