Sleeping Pad problem to solve

It might sound crazy, but how about a thin fitted sheet like twin sized?

Sew a couple of loops with wide grosgrain ribbon.

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I attach two small NeoAirs together for my wife and I with a couple of loops of 1/2 inch webbing. The loops make a figure eight around the pads, one at one end and a second at the other end. If you use full length NeoAirs you might want to use three or even four loops. It's not perfect, but it weighs almost nothing and works well enough.

You could use shock cord in a figure 8 horizontally around the two pad at 1.5 foot apart along the length of the pad with tension kept with cord locks it should hold tight. Plus you could use the extra shock cord as tie downs on your pack.

Or you could make a silnylon sheet with a vertical compartment for each pad sewn in the middle so the pads don't shift and you will also get a the added benefit of not slipping around on the pad and little added warmth and you could wash body grime off of the sheet and let air dry.
Terry

All your solutions are far too easy. Sure, a shockcord strap is cheap, will work perfectly and can be made in half a minute, but where's the fun in that? I suggest that you glue a zipper to the sides of your neoairs so that you can zip them together. It will be expensive, a lot of work and needlesly complicated, but it will be totaly awesome ;)

Take some sticky back velcro, inflate both mats and stick it on the sides should do the trick.