I really like the postcard with the photos layout. This was a great solution!
The phrase at the bottom, "Nothing can stop you but the ground." could use a little work. It makes it sound like you are going to hit the ground hard (to me!). And feels almost like a contradiction to the phase at the top "Be free & fearless".
I'd also prefer the 1st phrase to be a formatted differently. Maybe it's supposed to be more free-form, but it's looking a bit messy compared to the rest of the postcard.
On picture postcards, the stamp goes on the opposite side of the postcard (with the addresses and message), and it doesn't get the wavy lines until it's cancelled at the Post Office (in which case, it should have a stamp affixed). But I guess these can be forgiven, since otherwise it wouldn't be clear that it's a postcard, unless you add another postcard peaking out behind this one and have it facing the other way, showing the back. But then it would get confusing because it would be hard to show the difference of the photos being part of this postcard, but the two postcards being separate.
Overall, it looks really good! It would be cool for a skydiving company to offer this design, where you can insert your own photos.