First, hire a copyright attorney.
An attorney of anything I am not so this is my opinion.
Do you know what "Public Domain" means in copyright?
As they are your photos, they are yours to sell as you wish.
As I see it, unless there is something discernible and unique to those photos, then they fall under "Public Domain".
Let's say you take a picture of a car that's parked in a huge parking lot and nothing in that photo makes it unique.
That is public domain. Anybody could have taken that photo. Not just you.
Case in point, Ansel Adams took hundreds of photos of national park scenes and sold them.
While the scenes have been duplicate a million times over, any one else who owns that same photo can sell his photo as well.
But let's say you have a lovely young lady pose next to that car, or put her in that national park scene.
Now that photo scene becomes exclusive yours. Anyone else attempting to sell the same photo can be sued for copyright.
As for "unlimtied usage", I'd toss in a few.
E.G. If they wanted to use the photo in a tv commercial campaign.
I'd ask for royalties.
As for the FAA legal issues, there are none at this moment.
The NTSB has ruled that the FAA has no jurisdiction and can not fine under a law that does not exist.