I do my best to match what he's doing, yet every time I attempt a boolean difference on the wing it causes a load of holes to appear dotted all over the mesh, like so:

The bit where the cylinder was is absolutely fine, but the rest of the wing gets these weird gaps all over. I tried doing this without smoothing the wing, but this causes both the wing and the cylinder to vanish. is this because I'm using 2014 as opposed to the 2016 version I think the guy is using in the video? Up to this point buttons were just in different places... I can try to get a student version of 2016 if that's the issue, I just hope importing the project over won't be too hard!