The spectacular contrail spotted Monday off the coast of Los Angeles may have spurred widespread reports of a mystery missile launch, but Pentagon officials now say it was not a missile at all.

CBS affiliate KCBS recorded video of the unusual contrail near sunset on Nov. 8, and early reports suggested it was a missile launch from about 35 miles out at sea, west of Los Angeles and north of Catalina Island.

After an initial investigation, the military has quashed the "mystery missile" scenario, with many experts suggesting the contrail was caused by a run-of-the-mill jet aircraft.

"While there is nothing at this time that leads the Department of Defense to believe this is a missile launch, the department and other US government agencies with expertise in aviation and space continue to look into the condensation trail (contrail) seen and reported off the coast of southern California on Monday evening," DoD spokesman Col. Dave Lapan said in a written statement. [7 Things That Make Great Space Hoaxes]

"All DoD entities with rocket and missile programs reported no launches, scheduled or inadvertent, during the time period in the area of the reported contrail," Lapan added. "NORAD and USNORTHCOM confirmed that it did not monitor any foreign military missile launch off the California coast yesterday and has determined that there was no threat to the US homeland."

NORAD ? the North American Aerospace Defense Command ? worked in conjunction with U.S. Northern Command (USNORTHCOM) to investigate whether the contrail was indeed from a missile launch. NORAD is a joint U.S.-Canadian organization that provides aerospace warning, aerospace control and maritime warning for North America.

"In addition, the FAA ran radar replays from Monday afternoon of a large area west of Los Angeles. Those replays did not reveal any fast-moving, unidentified targets," Lapan said. "The FAA also did not receive reports of any unusual sightings from pilots who were flying in the area Monday afternoon."

"We did not approve any commercial space launches in that area for Monday, and any additional information should come from NORAD. That's pretty much all I can say right now," FAA spokesman Ian Gregor told SPACE.com yesterday (Nov. 9).

The U.S. military does, on occasion, conduct missile test launches and other weapons tests over the Pacific Ocean that are publicly announced.

On Oct. 29, the U.S. Missile Defense Agency conducted a drill with the Japan Maritime Self-Defense Force in a joint test of ballistic missile defense intercept capabilities. Photos and videos of that launch, as well as of several others conducted during the last few months, were released via the Missile Defense Agency's website.