Photographing flying birds, planes, etc

pretty good. Jets are hard to make look like they are moving. With props the trick is to not freeze the prop but blur it a bit.

Doesn't the sweet spot depend on the lens? For example, I've heard that my 50mm f/1.4 lens has a sweet spot of around 2.

F4

No, it's not a joke or myth. G spot? you haven't found it yet?   

Marian's 300mm zoom is f8

Maybe something like this

Could be something like this

Mike, you show off!! 

Marian,  He is right.  You need to compensate for both hand-holding and the motion of the subject with your shutter speed.  Mike may make it look easy, but he has practiced this a lot also, right Mike?  You need to keep practicing, try to stick around f/8 like has been said, it worked wonders for me when I got the same suggestion from the same person.  It may also be worth considering getting a monopod.  One other thing, when you can, use a lower ISO.  The noise will make otherwise sharp images appear soft as well.

One other thing, and I almost hate to bring it up, but what lens are you using?  I am pretty certain that Mike's glass is pretty high end.  It will be tough to match sharpness with him if you are using a much cheaper telephoto lens.  I hate to mention this because you need to be able to get the best out of the lens you have before you go out and spend a bunch of money that may not fix your problem, but it is a consideration for your future.  I had a Quantaray 70-300 for a couple years and couldn't get sharp photos at the long end of the zoom ever; I tried everything that was suggested to me, eventually I got a different lens and my images instantly became better.  You just need to be as sure as you can be that the lens is the issue before making a purchase so you aren't dissatisfied with your new one when you get it and find out it wasn't actually the lens.

Per your EXIF, at least on the planes and helicopter, I would think your shutter speed is too slow as Mike suggested.  On the birds, probably you were off with your manual focus.  I would suggest to keep practicing with the continuous auto focus modes on your camera.  Get out your manual and read up on it so you know how its supposed to work and keep practicing.  Also, I am again going to ask you what you have done on your edits, because if they were underexposed to begin with and you have tried to pull the details back out, you can deteriorate an image really quickly and cause some soft and noisy results like you have here.  Something to think about.

Travis

Oh, I'm not worried about hurting your feelings (that sounded bad) .  Really though, all I meant was that I didn't want to steer anyone into buying equipment that may not be the problem.  Oftentimes photographers think the solve all is new stuff, and it isn't always the case.

OK, let's go over your exposures:
U1 & U2 - 1/1000s f/16 ISO400  =  1/1000s f/8 ISO100  (pretty close to what's been suggested, I think)
plane1  - 1/300s  f/13 ISO100  =  1/750s  f/8 ISO100
plane2  - 1/125s  f/16 ISO100  =  1/500s  f/8 ISO100
copter1 - same as above

So you can have upwards of 1/600s as was suggested with f/8 and ISO100 at your current light levels.

There is one other concern though.  According to the Sunny 16 Rule (I know you like it) you should be giving one more stop of exposure in overcast situations, right?  That means that u1&u2 are underexposed by 2 stops; plane1, plane2, and copter1 are at least one stop under if not a 1 1/3 under.  RAW or not, if you don't get the proper exposure, you don't have the full amount of detail in the image.  RAW is better at preserving details and information than JPEG, but it is not a solution for poor exposure.  Keep working on your exposures, you will soon find that there is a world of difference in the final image when you get it right.

I know this is easier said than done, but keep working on it and practicing.  You have a great eye for great art; as soon as you get this technical stuff down to second nature you will begin to really enjoy photography more than you do even now.  Success precedes success.

Travis

So..., you're underexposing an already underexposed image?

No failings here, just learning hopefully.

Travis