Despite B757's being operated by FCA,TOM,TCX,XLA,BAW,AWC,MON,MYT,EXS,AEU,DHL and soon GSM non use winglets.
This suprises me given the benefits and the uptake by American operators.
I know the real benefit exists in the cruise and the longer the flight the greater the fuel saving.
Given that these operators regularly operate 4-6 hour sectors to the Canary Islands,Turkey,Cyprus,India,Africa,Canada and USA I find it strange in the present climate non utilise winglets.
The only reasons I can think of are initial costs and that many of these airframes are now comming upto 20 years old.