I’m on an Alaska Air flight (older style bird), and it appears the winglets are now sporting an additional fin below the wing…
First time seeing this for me …
It’s called a split scimitar winglet and is on many of the newer 737 series
Looks like it would be handy for chopping garlic.
Actually Aviation Partners Boeing did this to the older Blended Winglets to gain another 0.6-2.2% fuel savings. See http://www.aviationpartnersboeing.com/products_737_800SSW.php The new production aircraft are rolling off the line with new blended winglets, then do a retrofit for the lower part, and new winlet tip caps.
Also you will see more of these, or this style. Check out the new winglets on the new Boeing 737MAX http://www.boeing.com/commercial/737max/?cm_mmc=BCA-737MAX--AdBanner--GoogleSEM-_-Lang-EN
James