How much would a winglets conversion cost?

TIm questioned:

how much would a winglets conversion cost let’s just say on a 737 or 757 what hasn’t got winglets. Ive noticed that lots of airlines are now having the conversions done in view of the fact that of fuel efficiency.

How much would a winglets conversion cost?

TIm questioned:

how much would a winglets conversion cost let’s just say on a 737 or 757 what hasn’t got winglets. Ive noticed that lots of airlines are now having the conversions done in view of the fact that of fuel efficiency.