The whole model still could use a lot more optimization, and then the tris you save on that you can put into making the main fuselage and wings could be rounder, looks really blocky from the front view.
The Leading Edge of your wing needs to be much more rounded, both in terms of tris and smoothing groups. They are hardly ever pointy edges as you have them now, but smooth rounded fronts. I believe the SE has a "under cambered" wing section, giving it more lift, especially for slow carrier landings, at the cost of more drag / lower speed (its a sub-sonic aircraft), but even these have curved fronts, just smaller curved fronts from the more traditional types of wings you see on most aircraft. You can just make it out the cross section in the wing tip hinge area when they are folded up.
You don't have to make the wing section exact but giving it a few extra tris to make it its basic shape would help, mainly where it silhouettes on the round, leading edge, and just put in a segment on the bottom to indent it a little, but only needs one and let the smoothing groups do the rest
Also bunch of good refs here:
Super Etendard Modernis?e Walk Around Page 1
But ye, main thing to focus on is optimization, which will then allow you to add more detail. Try adding the Optimization modifier onto your model, just to see what it will do and give you some ideas of where you can optimize it. Don't leave it on or collapse it into your model, as it tends to screw you model up more than it fixes, as well as miss many optimizations you can do, but it should give you some ideas on where you can optimize manually. Also the Multi-Rez modifier is good for this, but again, don't leave it on your model, just to help you get some ideas but the lower its %, the more it will change the shape of your model it is getting rid of the tris, where the optimization modifier more just tris to keep the sameish shape, but remove unnecessary verts/tris, but doesn't do it very well.
And ye, worth modelling the air brakes, a bunch of our and vBF2 jets have them, and we have them come back when you go into "reverse throttle", and its a good visual indicator to other jets your slowing down, Tom Cruise won't be pleased thou as he would expect an instant super speed reduction from them thou

Make sure there is a big hole under them thou, as per r/l from what I can tell, so they don't zfight etc.
As for agus92 points, ye the back wheels need bigger chamfers, possibly more too, depending on how you go about it, on the edges, right now they look like blocks. Extending the axle out for them is also a good idea, and could do with some 3D detail
(but really basic, let the normals/texture do the detail, ideally from a HP bake as per the end of this post) on it for what I think are the breaks, too since they are pretty big on the refs.
Wouldn't do much 3D details, especially not for things like screws etc, since these will zfight, cost a lot of tris and/or look really block, and it is best to do them though a normal map.
The wheels is one area I would make a high poly model for, with all/most of the tiny details, and bake its normals onto the low poly model, since they have lots of detail on them which 1, you can't model without spending lots of tris and 2, can't hand paint easily when the texture artist comes along, which hand painting rivets etc onto the rest of the aircraft is pretty easy, as per what I said in post #32 of this topic:
'[R-DEV wrote:Rhino;2134369']Landing Gear / Wheels need far more tris, little lights etc need very few tris. The bigger the object, the more tris it needs (unless its flat or not requiring poly detail etc), the smaller the object, the fewer tris it needs.
Quick landing gear I made recently that might help:
And I did a high poly wheel for the normals (and AO + basic colour):

Anyways looks good so far and keep it up!

btw, might be worth putting a non-transparent material on the nose
