Some more info:
Found out that Coats PLC provide the global auto industry with the thread to sew airbags and seat covers, and that for seat cover seam airbag deployment they use bonded nylon in #45 weight.
However, the guy in the video bellow uses #69 thread:
The closest size thread I found so far was #46 on here: http://www.thethread...ylon-thread-046
or
#40 on eBay.
Stitching method:
The picture below shows lock stitching, what we do is lock stitch by hand, the other method (shown as hand stitching) is the absolute wrong thing to do. You do one loop with one needle, you do the second loop with the other needle through the first loop, and go on like that. Use pliers since the cloth is hard and hands sweat.