How to create a surface from the end of an extrusion

[Anonymous]

How can I create a surface from the end of this extrusion so I can extrude again.  Im trying to add wing tips to the end of the wings.  The wings are a symetrical extrusion of an airfoil sketch.   

[jeff_strater]

You should be able to do this.  Use Edit Form, select the outer edges (as in your image), then hold down Alt and drag:

Hope this works for you,

Jeff Strater (Fusion development)