Southwest Airlines on Friday began flying its first jetliner built with a secondary flight deck barrier designed to prevent intrusions in a design change that's been in the works since the Sept. 11, 2001, terror attacks.
The airline took delivery of a Boeing 737 Max 8 in recent days that flew from Phoenix to Denver and the flight serves as a milestone for the beginning of the new safety feature being deployed across new commercial airliners entering U.S. service in the coming years.
Secondary barriers have been sought after since the Sept. 11 attacks occurred after terrorists were able to force their way into cockpits and hijack the four airliners used in what became the deadliest terror attack in history. Aviation safety experts and pilots' unions have argued the secondary barriers will make jetliners more secure.
Boeing and Airbus told Reuters that they have begun delivering airplanes with the barriers in place under a Federal Aviation Administration (FAA) regulation from 2023 that took effect last week.
Southwest Airlines took delivery of its first Boeing 737 Max with a secondary flight deck barrier. (Kevin Carter/Getty Images / Getty Images)
The FAA said last month that it would give airlines until July 2026 to begin putting the barriers in newly-delivered planes to use.
Most major air carriers have told the regulator they intend to take advantage of the extension and won't put the barriers into immediate use ahead of the deadline.
Southwest has instead opted to immediately begin compliance and anticipates accepting the delivery of about 25 more Boeing airplanes this year that will have the barriers.
Southwest is the first major air carrier to begin using the new secondary flight deck barrier. ( Scott Eisen/Bloomberg via Getty Images / Getty Images)
"We felt like we could get it done and put it in production as soon as the aircraft was ready," said Justin Jones, Southwest's executive vice president for operations.
Following the Sept. 11 hijackings, the FAA adopted flight deck security standards that aimed to make them resistant to forcible intrusion and prevent unauthorized entry into the cockpit – an effort which preceded the new rule and has helped secure airliners currently in service.
Southwest Airlines also recently unveiled a revamped seat design for its new aircraft deliveries. (Southwest Airlines / Fox News)
The FAA's newly-implemented rule requires aircraft manufacturers to install a second physical barrier on new planes used in commercial passenger service in the U.S., but doesn't require that existing planes be retrofitted.
Planemakers without FAA certification of barriers don't yet need to be in compliance with the regulation.
Reuters contributed to this report.