The post-processing is a bit heavy... if this were a landscape picture. For machinery and other city-scape or other urban subjects, I think that heavy post-processing is entirely acceptable if not preferable.
In the first one (F4U Corsair), I think that the wing is too heavy. There's a lot of dark negative space under the wing and the leading line of the leading edge of the wing is really long. I think that a leading line should lead to a focal point of the subject or the subject itself. In this case the line is very long. Plus, that line ends up being a high contrast line between above/below the wing that it keeps my attention there.
Also, the Corsair has an interesting feature that works against you with the inverted gull wing design: the leading line ends up pointing too far down and pulls the viewer's attention away from what might be the better subject.
I think the more interesting part of the picture is the multiple edges and rivet work around the fuselage and the cockpit area. If you cropped the picture to be less wide it might reduce the too heavy feel of the wing. However, it also cuts into the landing gear which could either lose interest or just become an awkward crop.
In the second one, the cropping puts the emphasis around the engine/prop/nacelle area which I think works. It might not be the most exciting subject for this genre but visually I think it's clear to bring my eye to a specific point in the image. I like this one better than the first.
