Your parts look pretty clean, what settings are you using? I find mine get some under extrusion in places.
We got that from a lot of fussing. But if you don't have it, Simplify 3D is worth the money. Although not perfect, the prints came out instantly better switching from Cura to Simplify 3D. Not to say you can't get great prints using Cura, but Steppan already dialed this in for Simplify 3D, so you don't need to mess with the settings as much.
After that we played with the extrusion settings, upping them by .02 until it came out okay. Sometimes we had to slow the print down as well (we found that the percentages in S3D are the percent of the speed already in the settings. So if the print is set to print at 60%, then you slow it down by 50%, you are really slowing it down to 30%, or 50% of the original 60%), and we constantly adjusted the retraction settings. We found, and I think Andre found the same, that the settings for the wings and fuselage are different.We had it locked in for the wings, then when we started the fuselage, they came out very thin. My buddy completely cleaned his printer, replaced the bowden tube (Capricorn), bought a bunch of cheap nozzles so he could just toss clogged ones, and he'd run some Rigid Ink floss through to clean it out if he felt it was getting clogged, but not enough to junk the nozzle. Then he ran it pretty much the way the settings were in Simplify 3D.
We were surprised to discover that 3D printing is more of an art than a science. We found that for each section, we'd take the smallest piece and run it until it came out as clean as we could get it. Sometimes it would only print for an hour or two before you'd see something was wrong. Then adjust and try again.
So we took the S3D settings, then adjusted the extrusion by .02, and the retraction settings, and even speed if necessary, until we like what we saw. Since each printer has it's own identity, you'll have to play around with yours until you find the best set up for your particular printer. Finally, check for clogs. High retraction settings cause clogs. Even small ones can cause less filament to flow, causing underextrusion. He actually ran a test, not sure what it was called, but he ran a test that measured the amount of filament that was supposed to flow through the extruder. In the test, the system said 100mm should have flowed, but only 80-something flowed. That's when he replaced the bowden tube (by-the-way--the Capricorn Bowden tube had so much less friction, we had to lower the retraction settings after putting it on) and nozzle. In one of the later prints he found the opening at the tip of the cheap brass nozzle had been worn away and was a rectangle. not sure if it was the clear filament, or if that was because they were cheap brass nozzles. But this model requires a TON of printing, so just stay on top of the hotend, and play with the settings, and you should be able to dial it in.
Oh, and he also got rid of the glass bed that came with the Creality CR10. They all have a bow in them somewhere, and it makes it totally impossible to level.
Hope that was at least a little helpful. Good luck!