It is hard to give you the definite answer in this situation because I don't really know the specifications for the end wings. If you just want a round end, there are several ways to do it, and each would give you different shape. Thus change the result of your analysis.
I attached one way to closed a loft. Keep in mind that there are other methods that may give you your desired shape.
Also, using two sepereate loft or two seperate features to create the wing is not necessary the wrong choice.
Closed loft.SLDPRT.zip 159.3 KB
I noticed my mistake: Neglecting to include a point (created as a separate sketch at the tip of the wing) in the loft options.
I thought you could only include closed sketches, not just points.