Missing the key point. Aircraft are updated with newer avionics after leaving the factory quite routinely. Considering Southwest currently has 122 737-300s in

Missing the key point. Aircraft are updated with newer avionics after leaving the factory quite routinely. Considering Southwest currently has 122 737-300s in service, they wouldn't upgrade them if it wasn't available at a reasonable cost: http://www.airfleets.net/flottecie/Southwest%20Airlines.htm http://www.airfleets.net/flottecie/Southwest%20Airlines.htm Cockpit upgrades for 737s: http://www.aviationtoday.com/av/issue/feature/Product-Focus-Cockpit-Displays_77438.html http://www.aviationtoday.com/av/issue/feature/Product-Focus-... Cockpit upgrades for C172 type aircraft: https://flyhpa.com/2012/08/the-garmin-g500-g600/ https://flyhpa.com/2012/08/the-garmin-g500-g600/