I think 40 feet might be needed to make a belt like that. Each inch of that belt would probably take as long a cord as was needed to make an inch of my landyard. I used a total of about 9 feet for 8 inches. So 40 feet of cord with that belt would get you about 32-36 inches of belt. It might take more cord. Your cord would not be all in one length, but there are worst thigns to deal with, like no cord with you at all.

That belt would also get you past security without having to take off your belt.

In addition to the BSA sparker, you can probably get on a plane with a P-38 or P-51 can opener. It's a poor choice for many jobs, but it also has been carried by me onto a plane and into a courthouse, which has similar restrictions.