Why good Wi-Fi is so hard to get on airplanes

Airplane Wi-Fi has been around for decades but its reliability and speeds can vary widely depending on the airline, the route and the type and age of the aircraft. American Airlines, United and other U.S. airlines have been updating their fleets to provide better wifi. Delta has spent over $1 billion retrofitting its planes to bring free wifi to its customers. CNBC got an inside look at how Delta is working to upgrade over 1,200 planes by 2024.