https://www.theguardian.com/technology/2022/jan/17/us-airline-officials-crisis-5g

Introduction of the new technology near airports could interfere with critical airplane instruments such as radio altimeters

US airline chiefs have warned that the introduction of a new 5G service could cause US commerce to “grind to a halt” due to possibly grounding a significant number of aircraft and might “strand tens of thousands of Americans overseas”.