Technology has advanced. In every aspect of life we are looking at ways to better engineer solutions and products that we develop.
Let's look at sport. Formula 1 teams are looking how to change one piece of the body to get that advantage over their competitor. A cyclist riding the Tour de France might have a new shoe that allows him to save energy and win by a second and change his life forever.
In aviation, aircraft manufacturers are constantly striving to better themselves and develop more fuel efficent aircraft.
The thing on the edge of the wing comes to mind.
Airbus's "winglet" seen below. I'm not so sure the engineering stacked up but they knew they had to do something.
Airbus then furthered their development of the winglet and implemented the Sharklet. The following extract is from Airbus
"Airbus’ next step is the large Sharklets™ wingtip devices, representing another element in the ongoing continuous improvement programme for its best-selling A320 Family. These devices improve aerodynamics, reducing fuel burn by up to 4 per cent – which amounts to annual savings of more than 900 tonnes of CO2 per aircraft. "
Boeing's winglet on their 737 is a standard sight these days.
It's about getting more efficeny out of the aircraft, saving fuel and thus saving money for the airlines.
There seems to be on going legal battle over the design of the Sharklet and the Winglet.
What is for sure though is that it plays an important in the marginal gains that aircraft have developed over time.