Among the top tennis strings on the market, nylon or polyester string is most often used. Nylon is used in so called monofilament strings; multi-filament feature nylon combined with strings such as polyester, Kevlar, Vectran, etc.

Usually people ask this because they remember the tragedies of the past. The Airlander is incredibly safe compared to the blimp style aircraft of the past. It uses helium, which is an inert gas that *cannot* catch fire, instead of hydrogen like the R101 and the Hindenburg. Its hull has three different layers, and one of them is Vectran, which a material that is five times stronger than steel. It can fly in high winds of up to 80 knots, the highest level on the Beaufort wind scale. It has a top speed of 100mph.

No one can (or should) say that any mode of travel is completely safe. That would just be tempting fate. But it seems clear that this craft is not going to repeat the tragedies of the past, because it is better made and there cannot be any Hydrogen accidents where there is no Hydrogen present.