What are some unique engineering challenges in designing large, widebody aircraft that do not apply to regional/corporate jets? In terms of appearance, the Embraer 170/190 series aircraft look similar to their larger counterparts.Jets of all sizes have similar ceilings, airspeeds, and life support needs. If Embraer (or any RJ maker) were motivated to do so, could these smaller airframes be scaled up / elongated to fit 300+ pax? What new challenges would be faced in designing a widebody?
Technically, designing and manufacturing narrow-bodies does not differ much from designing wide-bodies. Sure, the scale is different, heavier jet engines, larger factories etc, but in principle the engineering issues to be solved are pretty much the same. Airbus' first design, the A300, was a wide-body. Sure, Embraer and others can utilise their experience for designing and manufacturing wide-bodies.

The real challenge is in the size of the market, and in conquering market share. Only Boeing and Airbus make successful wide-body aircraft. The combined deliveries per year for wide-bodies are a bit over 200 for all types, for narrow-bodies over 1,000, gearing up for > 1,100 in a couple of years.

Image source

Industrial issues to be tackled for starting a wide-body plant:


The investment for designing and starting a manufacturing plant are higher: harder to secure capital.
The market size is smaller: securing a number of unit sales equates to conquering a more sizeable portion of the market than with narrow-bodies.
There are two well-established manufacturers with multiple types each, in multiple variations, cornering all segments of the market.


Very hard to compete here. Much better to scale up the regionals into the narrow-body sector, like China did with the C-919.