As to airspace classes Airspace class (United States) - Wikipedia is pretty good and about as approachable as the topic gets. Looked at with a magnifying glass it starts to resemble the tax code. But the big picture isn’t too hard. Class A is most controlled / restricted and as we go farther along the alphabet the restrictions reduce.
Crudely:
A = High altitude enroute everywhere: 100% IFR. 100% radar. 100% ATC access controlled.
B = Major airline airports and ~30 mile vicinity: 100% ATC access controlled. 100% radar. VFR permitted only w ATC concurrence and control.
C = Lesser airports with radar-equipped local ATC & ~10 mile vicinity: 100% ATC communication required, but VFR access not controlled.
D = Airport with a control tower & ~5 mile vicinity: Tower visually manages aircraft arriving & departing, tower notification required for aircraft transiting.
E = Low-mid altitude enroute everywhere: IFR operations under ATC control, VFR operations permitted w/o ATC contact or knowledge. Most, not all, areas have radar coverage depending on altitude.
F = US doesn’t have.
G = Near-ground airspace everywhere including uncontrolled airports: ATC completely hands-off; pilots (including IFR) are 100% responsible for safe nav, collision avoidance, etc.
As to paperless …
My carrier has been 100% paperless for about 3 years now. It’s all in our issue iPad. Arrival / departure charts, enroute maps, procedure & aircraft manuals, today’s weather & flight plans, performance computations, the whole shebang. It’s all delivered through 5 primary apps and a handful of rarely used auxiliary apps.
The current effort is essentially v2.0 where we’re duplicating all the old paper ways but with a few tweaks and integrations empowered by tech in general and more and more by having live wifi nearly everywhere all the time.
The v3 in the works involves a massive overhaul of the legacy ground systems to integrate everything down there so it can be delivered up to us via a single do-all
app with a single do-all interface.
As well eventually the tablets will interface directly with the aircraft avionics; right now they are heavily firewalled off from each other.
Most major US airlines are in about the same place now.
Conversely, private pilots in lightplanes through bizjets have been able to do most of these same things since the early 2000s. They were definitely the leading force here and the big guys have been taking up the rear. In fairness, FAA took their sweet time getting on board with the idea.