CPH-R From Denmark, joined May 2001, 5866 posts, RR: 3 Reply 3, posted (12 years 1 month 1 week 12 hours ago) and read 645 times:
lol @ frascaman
Anyway, without being overtechnical:
In flight, a pressure envelope is created above the wing, which then provides lift. The air underneath the wing will of course try to get on top of the wing, and thus even out the different in pressure. By adding the winglets, a form of fence is created which then makes it harder for the air to move from below the ving to the top of it. By adding wihnglets, you get an improved flight dynamics, and thus you can fly further with the same amount of fuel.