The big deal planes manufacturers have to face up with is to generate enough lift (the force pulling upwards) to take the aircraft in the air.

The key factors in generating lift is the amount of air interacting with the wing each second, and how good the wing is in using this air. To increase lift, one can then:

1. Widen the wing
2. Make the plane faster
3. Design more efficient wing

Wider wings have limitations, because building large nearly flat structure requires extremely resistant, thus heavy material. This is where new generation of composite materials do help a lot. Carbon and glass fibers have excellent mechanical properties, while being relatively light compared to aluminum. All new generation airliners incorporate such materials at wide scale.
Another limitation to wide wings is the practical aircraft maneuverability, both in the air and on the ground.

Higher speed is not really a solution. Increase of speed will certainly lead in increase of lift, but it will require more thrust, and probably heavier engines, calling for more lift… Moreover, as runways are not infinitely long, an aircraft shall be able to fly at relatively low speed for take-off and landing, also for ground-roll controllability.

The third factor, efficient wing design, has also been subject to constant improvement. Modern wings don’t have a lot in common with Wright Brother’s ones, despite all respect due to the very first plane. For a while, design was based on experimentation, as physical modeling of airstreams requires huge computational power.
Computer Aided Design (CAD) not only made development cycles shorter, but it also allowed for a lot of wing optimization and improvement.

Finally, and this will be the subject of next post in this series, engine technology also evolved a lot. An additional environmental concern about engine noise lead to some sacrifices in performance, but this is a political thing…

(This post was the second in a series about airplanes and environment. First post in the series was about Jet-A1 vs AVGAS engines. )