I'm not sure what "catastrophic" means anymore! At least in Politics.
As for "5G and aircraft", I think there is way too little research and information. And, since the FCC sees selling radio frequencies as a way of cutting the National Debt, it is of little use in
protecting anyone. Meanwhile, the FAA has been quietly trying to mend it's recent lapses of trust and has few resources to pay for the studies needed.
Supporters of "5G" claim that it is being used "all over the world" with little impact (an ironic term to use, in my humble opinion!). My question would be; what are those countries and how many of the airports have Cat III approaches. Just as importantly, how many of the airlines operating in those countries have aircraft or crews certified to use Cat III equipment?
"Cat III" equipment allows certified aircraft and crews to fly almost all the way down to landing on the runway. Some equipment can actually land the aircraft, regardless of the visibility, without the pilots ever seeing the runway. I can only assume that these types of approaches and landings are what is included in the "very little impact" 'collection'.
But the actual equipment that can be affected by the frequency duplication/interference is used on almost all landings in commercial service. The affected equipment is called a "radio (and sometime incorrectly, 'radar') altimeter". In most modern commercial (cargo and passenger) aircraft, the crews get verbal cues on every landing as to their actual distance above the (hopefully) runway. Those verbal cues are announced every ten feet: "30", "20", "10". Sometimes there can also be "50" and "40" callouts.
An aside: There is no "Contact" or "We're on the ground" calls,
most pilots just listen for screams or applause from the back for that
confirmation. 
I hardly ever carried passengers, so I would often
ask the tower if we were on the ground. A secondary confirmation was
when the Spoilers activated, that required weight on the wheels.
But I digress...
The potential problem is that when/if the 5G equipment affects these altimeters, a landing may
not be conducted safely. Fifty feet above a runway is not a good place to start thinking (or even worse, talking) about what is happening! Many aircraft even have minor system warnings inhibited in these situations to avoid distractions to the crew during this most critical part of a flight.
If any of you have owned any kind of aircraft, you will already know that anything labeled for use in one is always at least double the same part that might be used in a car! Multi-million dollar airliner parts are even more expensive. Most large commercial aircraft have multiple installations of the same item; 2 or 3 engines-check, 2 pilots-check, 3 to 10 fuel tanks with duel pumps-check, etc. Radio Altimeters are the same there will always be 2 and often 3 installed. Who will pay for designing, testing and replacing these? And, how long will all that take? That's why most pilots laughed when one of the telecoms said they would delay their rollout for two weeks.
I am just praying that we won't have to wait for safety changes to come in the historical way — the tragic crash of an aircraft. And yet commercial flying is still the safest way to get from any point in the US/Canada/Europe to any other place in those countries. Your trip to the airport will be much more dangerous!!
Write your Congressman and Senator and hope they can read and understand facts!
I frankly fear there are fewer and fewer of those around, however.
