The Switchblade is a proposed unmanned aerial vehicle being developed by Northrop Grumman for the United States. The United States Defence Advanced Research Projects Agency (DARPA) has awarded Northrop Grumman a $10.3 million (USD) contract for risk reduction and preliminary planning for an X-plane oblique flying wing (OFW) demonstrator.G. Warwick - Flight International, Num 5029, Vol 169, Pg 20.

a pocketknife with a blade that springs open at the press of a button

a single edged automatic knife

is any knife with a blade that folds, closes, or retracts into the handle or sheath and that opens automatically by pressing a button or by the force of gravity or centrifugal force.

Switchblade is a 1994 album by Schaft.

a terrible idea unless you're in a vrey bad part of town

Joint project begun on 15 December 1969 in which three Vietnamese land clearing companies were assigned to the U.S. 62d Engineer Battalion for training and deployed with their counterparts to War Zone C for forty-five days of land clearing operations in support of various U.S. combat units[232