In 1959 the U.S. Navy submarine USS Barbero assisted the Post Office Department, predecessor to the United States Postal Service (USPS), in its search for faster mail transportation, with the only delivery of “Missile Mail”. On 8 June 1959, Barbero fired a Regulus cruise missile – its nuclear warhead having earlier been replaced by two Post Office Department mail containers – targeted at the Naval Auxiliary Air Station at Naval Station Mayport in Florida. The Regulus cruise missile was launched with a pair of Aerojet-General 3KS-33,000 solid-rocket boosters. A turbojet engine sustained the long-range cruise flight after the boosters were dropped. Twenty-two minutes after launch, the missile struck its target.
At Mayport, the Regulus missile was opened and the mail forwarded to the post office in Jacksonville, Florida, for sorting and routing.
Back during the “War on Terror” era, when you had some defense contractors with no longer a Soviet Union but not yet a China and trying very hard to figure out some way that they could possibly sell their products when what the Department of Defense was mostly interested in was in dealing with random terrorists in a desert somewhere, I remember some torpedo manufacturer trying optimistically to sell a torpedo designed to deliver special operators to beaches.
You might need to get them there more-quickly, and the Navy has experimented with other options.
https://en.wikipedia.org/wiki/Rocket_mail
Back during the “War on Terror” era, when you had some defense contractors with no longer a Soviet Union but not yet a China and trying very hard to figure out some way that they could possibly sell their products when what the Department of Defense was mostly interested in was in dealing with random terrorists in a desert somewhere, I remember some torpedo manufacturer trying optimistically to sell a torpedo designed to deliver special operators to beaches.