The most cramped cockpit I've been in was the B-1. You wear that aircraft. The
Mig-21 was tight also, but you had a sort of bubble canopy to help.
Put 2 200 pound guys in a Cessna 150 and that's the definition of tight!
As for autodrive in cars, the problem is MUCH more complicated than an
aircraft autopilot. The enviroment that cars operate in is a whole order of
magnatude more complicated. Cars have to contend with other drivers,
twisty roads, pedestrians, very complicated weather. All of these are changing
in a very illogical way very quickly.
An autopilot just does a few things. It holds an airspeed, course, track, or
altitude. Add in an flight managment computer(FMC) and it will climb, descend,
or change airspeed within very strict paramiters. Most of these have to be allowed
by the pilots.
It has no outside sensors to detect dangers like other aircraft or the ground.
Most airliners have low speed protection if the auto throttles are engaged AND
in the correct mode. The Asiana pilots had the auto throttles in the "Level Change"
mode which always gives either max thrust or idle thrust. Since they were descending
it commanded idle thrust. They did not understand this and tried to control the flight
path by pitching the nose up. The FBW prevented them from stalling the aircraft, but it
did not have the energy to safely land at the airport so it hit the sea wall. In this case
the FBW saved many lives because the pilots were so clueless that they would have
stalled the aircraft well before the airport and dropping into the bay killing everyone.