[goodcanadian]

Side question: is fly-by-wire an obviously good idea for passenger airplanes?

Fly by wire is about removing the weight and complexity of mechanical control systems. A pilot wouldn't likely have the strength to move the controls without fly by wire. However, I don't think that's what you are asking. Fly by wire does not inherently have to be computer assisted; it could simply translate your input to a control surface movement without interpretation. Of course, to get any kind of feedback, it is going to have to be computer generated. The question is where to draw the line.

Finally, you compared Airbus to Boeing. Both are fly by wire. The difference is, I guess, that the control yokes on Boeing are mechanically linked to each other but not on Airbus. However, from the yokes to the control surfaces is fly by wire either way. My understanding is that the difference is in philosophy of how much the computer does for you.

I hope I got all this right.

[bencpeters]

Mostly right! Fly by wire doesn't inherently have to do with whether a pilot has the strength to move the controls or not - airliners in the pre fly-by-wire era still had hydraulic actuation of control surfaces, which allow pilots to multiply the force of their inputs. The main question/difference here is how much physical feedback the control system gives to the pilot - basically how much harder to move the stick it gets as the actual pressures on the control surface increase. Whether it's an electronic system or a hydraulic one in between the cockpit controls and the surfaces doesn't HAVE to mean that the physical feedback is all that different. It does make it easier to do non-linear ramping of the feedback though.

You also can do more complicated mappings of control inputs to control surface movements more easily with FBW (you can think of automatic traction control in a car as a somewhat analogous system - it uses differential braking per wheel, which the driver has no direct control over, to attempt to straighten out the path of the car and follow the driver's inputs from the steering wheel). As another comment mentioned, this has been happening in fighter jets for a long time, mostly due to how inherently aerodynamically unstable they are.

[baybal2]

I wonder, how in the world non-hydraulic assisted airliners flew?

[teruakohatu]

They would have used pulleys and I think they still do:

https://www.ralmark.com/aircraft-pulley/overview/

[Animats]

The control cable system of a B-52 looks like something that belongs on a bicycle. Steel cables on big open pulleys.