Hi flyers!
I cooked up... and have tested on an AA 737-800, a working solution for my Samsung 12.2 tab.

I have an ELV hard case on it, into which I drilled a tiny hole in each top corner with a Dremel tool. Then I put in a small screw eye in each hole, and epoxied them for security.

Finally, I found an old nylon strap, about 24 inches long, probably from a cheap camera. It has snap clips on each end, which clip to the screw eyes when needed. I also clipped a carabiner into the loop, just in case I need it to hook to something.

On AA, in coach, the strap looped perfectly around the seat top in front, in the slot between the back rest cushion and frame.

Upright or reclined, worked perfectly. Guy ahead of me never knew.

I have a bluetooth sharkk keyboard and a bt mouse, so i can recline, operate the tab without reaching forward and even get some work done. Or more likely watch old movies on playlater!