The telecoms and aviation industries went head to head in the United States this week over 5G, a technology that's constantly finding itself the subject of controversy. Just as AT&T and Verizon began switching on their 5G masts, major US airlines warned of a "catastrophe" should the network interfere with planes' ability to land. FRANCE 24's Technology Editor Peter O'Brien explains the technical details, and casts an eye over the future of cellular communications worldwide.