Originally Posted by
grizu
AFAIK winglets improve fuel efficiency during flight but increase fuel consumption for take off and climb.
But how, and why? Efrem's post provides the real answer.
Using winglets increases lift and therefor shortens the take off distance. It also shortens the distance between two successive aircraft. I don't think the highlighted part of your claim is correct. I can't think of any reason why it would increase fuel consumption during take off and climb.