"The Daring Dufas" wrote in message
news:kscsg4

stuff snipped

I seem to recall small blimps in the air over London during WWII to
tangle up low flying enemy aircraft.

http://en.wikipedia.org/wiki/Barrage_balloon

A barrage balloon is a large balloon tethered with metal cables, used to
defend against low-level aircraft attack by damaging the aircraft on
collision with the cables, or at least making the attacker's approach more
difficult. Some versions carried small explosive charges that would be
pulled up against the aircraft to ensure its destruction.* Barrage balloons
were only employed against low-flying aircraft; the weight of the longer
cable made them impractical for higher altitudes.

*That had to be a nasty sound, when the aircrew heard the cable snag and
then "twang" until the bang.

--
Bobby G.