I've gotten (luckily) to fly on some not-tiny airplanes in my life, and gotten to sit with the pilot for the flights. Every single time, I leave impressed at the efficiency of the ATC moving all of these things around cities, in and out of airports, etc.
This is largely due to the improvements in Secondary Radar [0], Transponders[1] and TCAS[2]
[0] https://en.wikipedia.org/wiki/Secondary_surveillance_radar
[1] https://en.wikipedia.org/wiki/Transponder_(aviation)
[2] https://en.wikipedia.org/wiki/Traffic_collision_avoidance_sy...
Incidentally, the biggest aviation accident in history (Tenerife) still can be felt today in how the FAA trains ATC personnel and how they choose the language that is authorized for use by ATC.
Practically every pilot has heard of the Tenerife disaster, and is commonly discussed in flight schools. A lot of safety changes in aviation can be tied back to previous mishaps. In Naval Aviation, the flight standards program is known as NATOPS [3] (Naval Air Training and Operating Procedures Standardization), and the phrase "The NATOPS has been written in blood" is largely because it dramatically reduced the mishap rate, and changes are often as a direct result of previous mishaps.
[0] https://en.wikipedia.org/wiki/Hughes_Airwest_Flight_706
[1] https://en.wikipedia.org/wiki/1996_Charkhi_Dadri_mid-air_col...
[2] https://en.wikipedia.org/wiki/1986_Cerritos_mid-air_collisio...
[3] https://en.wikipedia.org/wiki/NATOPS#History.2Fraison_d.27.C...
I'm constantly shocked by not only how well traffic controllers do their job, but how serious they seem to take and how courteous and helpful 99% of the controllers are, both in regional approach/departure TRACON and large center control such as Miami, Jacksonville, Atlanta or Houston.
The majority of the goals of what they are trying to do with "NexGen"[1] is primarily moving all aircraft to more effecient GPS routes, which are for the most part already in place and getting airplanes to talk to each-other 2 way with ADS-B in and out. Of course every pilot is going to have a different opinon, but as others have stated my experience has shown that the FAA has done a decent job of accomplishing that mission without completely disrupting the current air traffic control, and of course it's not ideal it's still as good as you can hope for givin the constraints. We have a tendancy of blaming the government of being too beurocratic, but the implimentation of current next-gen policy has been not only pragmatic but mostly sympathetic to the fleet of aging General Aviation. [2]
My experience are this: I can get in my plane, file a flight plan to an airport in the next state, ask for GPS direct and get traffic awareness of about 80% of the planes in the sky directly and the remaining 20% are sent to my plane via ADS-B. I'm not having to fly using only Victor Airways reliant on aging VOR stations I'm having NEXRAD radar streamed into my cockpit, including weather TAF and METAR updates at airports. Other planes in the sky know where I'm at as well. A lot of this can be done with a small GPS box and an iPad. (And yes, I know ADS-B out is only certified installed equipment) But foreflight and many other solutions are here, the ADS-B recievers are cheap and it works today. [3]
All of this has only been available over the last few years because of ground work and policy that has been being pushed over the last 2 decades, and is within reach of not only the largest air carriers but even the student pilot just getting his start.
[1] https://en.wikipedia.org/wiki/Next_Generation_Air_Transporta... [2] https://www.faa.gov/news/fact_sheets/news_story.cfm?newsId=2... (* Rebate programs and other incentives to help get people into new equipment) [3] https://www.foreflight.com
https://www.oig.dot.gov/sites/default/files/WEB_ATC_Mod_4-14...
Basically, FAA's nextgen project has been some big dig level crap (https://en.wikipedia.org/wiki/Big_Dig for those not familiar)
They've been trying to figure this out for almost 3 decades (though publicly, the current incarnation only started to have a joint planning office in 2003, and so they try to pretend that's when they started).
They currently don't expect to finish until 2030. AFAIK it'll have been ~50 years for a technology modernization project.
(I actually don't know all the details, so if someone wants to come along and say "it's not that bad", great!)
Good watch if you wanna see how naively designed the whole thing is.