Hi there! I remember you found an image of a pilot taking a selfie "mid-flight" and then the original image below it, which was in an airport. Do you have an idea of how the photoshopper was able to change the reflection on the body (blue part) of the aircraft? Thanks!

I think I can be of assistance.
First you must mask out the plane. You can use the pen tool or polygon lasso to cut around everything. I recommend zooming in to 800% so you get a lot of accuracy with your selection. Once your selection is done, create a layer mask from it.

Next thing is add a nice sky background. Just copy and paste behind the plane.

To get the reflection, add the sky background again on a top layer. Free transform and warp it so it roughly has clouds over the place you want. I gave my clouds a good spherizing filter so they had a warped look to them.

Do your remember that layer mask you created for the plane? If you control + click on that mask, you can bring back the selection. Now you can add a layer mask to our mess of clouds here. Change the layer blending mode to Soft Light.

Soft Light may not always be the right choice. You’ll have to play around with the different modes to see what works best with your image. You can also reduce the opacity if they are coming in too strong.
Now we need to do some clean up. I recommend just getting a large eraser with hardness set to 0%. (heh, hardness) Slowly eat away at the spots where you don’t want the clouds reflected.

The next step is to add a nuclear holocaust. Find yourself a nice mushroom cloud and bring it into the picture.

With a soft eraser brush, just eat away at the bits you don’t want. This doesn’t have to be super accurate. A little softness on the edges will help it blend. This particular mushroom cloud has way too much yellow. Using Hue/Saturation, I went to the yellows and just dragged the saturation all the way down. Then I moved the cloud into place.

Add an orange photo filter to the clouds to make them a bit spooky.

Let’s give that fella a laser.

Just fill a selection with white and add a green outer glow.
OH NO THE ENGINE BLEW UP!

Find some fire on a black background and set the blend mode to “screen.” Add smoke with soft brushes on low opacity. Just build it up one click at a time until it looks smokey. OR, you can find smoke brushes on the internet. Don’t forget to duplicate your firey engine in the plane’s reflection!
And the final step is to add some aliens shooting nuclear death beams.

Just click the “alien death beam” button under the “Filter > Noise” menu.
I hope that helped!