Lockheed C-130 Hercules (N3867X)

Wow! pretty discrete looking. Any idea which branch they might be?

I'm going to say it isn't "military". I believe Chris has captured a photo of a Tepper operated "civilian" Lockheed L-100 Hercules freighter...

https://en.wikipedia.org/wiki/Lockheed_L-100_Hercules#/media/File:Tepper-l382-N3867X-061120-03cr-10.jpg

Thanks Cliff.

You're welcome, Chris... and thanks for sharing this Hercules at high altitude with us.

Thanks for the intel, Cliff!

R X, you are welcome... and yes, it does appear discrete!

What is the L-100 tag for this plane on flightaware?

According to the JO 7360.1B (Aircraft Type Designators), its still a C130 for classification purposes which is what I think this program runs off of.