(the )silk

   a parachute

   Euphemistic only in the phrase on the silk, referring to a military air crew obliged to abandon an aircraft in flight:

    ... you've got to stick to your own air space or ride down on the silk. (Hackett, 1978 — if you collide you will crash)

   Whence the figurative hit the silk, to seek to escape from or avoid a calamity, as by using a parachute:

    In markets like this, if that happens, everyone'11 hit the silk at once and no one'll get out the door. (M. Thomas, 1987)