[Catfish]

Regarding the german airships, parachutes were already available at the beginning of the war, but as mentioned before they were left behind voluntarily to improve performance, and bomb load.
When the "height climber" airships arrived on the scene, some did indeed carry parachutes again, however the crews often decided not to put them aboard – it was not an order though (I really do not understand why, i most probably would have ..)

Later in the war, smaller-packing parachutes became available for pilots of heavier-than-air crafts, too, at least in Germany. A lot of pilots used their chutes, and were thus able to live on after their plane was wrecked (e.g. Ernst Udet being among them).
The british high command did not trust parachutes, while of course being ungainly and hindering free movement in the already cramped cockpits and adding weight to the already underpowered planes, they assumed a pilot with a parachute would tend to abandon his expensive plane in dire situations, instead of fighting on to the end.
Contrary to popular belief, the british military was much more harsh with decisions and executions, when it came to enforce discipline within its armed forces, than their prussian (=hunnish a.s.o.) counterparts. God knows how much pilots would have been rescued without this decision, especially with regard on the "training", british pilots and observers received in this first air war.