What were they doing out there? I have no idea what the tail ID means.

Civilian contractor aggressor squadron.

For the last 20 years, Airborne Tactical Advantage Company, or ATAC, has trained Navy, Marine, Air Force, Army and International aircrews, ship-crews and Combat Controllers/JTACs in the air-to-air, air-to-ship, and air-to-surface arenas. From five major locations world-wide, including the Continental US, Hawaii, and the Pacific, ATAC has trained the finest warfighters with over 65,000 hours of tactical flying support. ATAC has trained at the US Navy's elite Fighter Weapons School (TOPGUN), the US Marine Corp's Marine Aviation Weapons and Tactics Squadron One (MAWTS-1), and at the United States Air Force's Weapons School. We firmly believe it is our mission to assist in Training Today's Warriors for Tomorrow's Challenges.

https://atacusa.com/

Awesome! Wish I had seen them!

Ok that’s pretty cool... I did not know that.

I think I did, they were far away so it was hard to tell what they were, but they were loud.
The planes I saw were heading East, I assumed they came out of McDill.