Learjet incorporated winglets on their test-bed aircraft (model 28),
making it the first production jet aircraft to use them;
resulting in a 6.5% increase in range and improved directional stability.
Boeing followed suit 8 years later, with the introduction of winglets to itís 747.
Known as the 747-400 it boasted extra capacity and increased range of about 3%.
The pelican in this photo has nothing to do with Kiritimati
but it does have wing tip feathers.