News footage[a] of the event from a KCBS helicopter led to intense media coverage and speculation about a potential military missile launch, with many reporters and experts discussing the contrail and theorizing about its source.

[6][5] While some uncertainty over the vapor trail's origin persisted,[6] the incident came to be seen as an example of news outlets being "captives of their sources" and irresponsibly pushing unverified theses; it was also interpreted as a lesson in the importance of exploring alternative hypotheses that fit available data.

[6] U.S. federal and military authorities were also criticized for giving a series of "inconclusive" answers about the event and allowing the issue, in the words of one commentator, to "fester for days" without a clear resolution.

Contrails, short for "condensation trails," are linear cloud formations produced by aircraft exhaust or air pressure changes, usually at commercial cruising altitudes several miles above the ground.

[16][17] The San Clemente "New Year's Eve Contrail" was a horizontal trail at about 32,000 feet, or six miles, in altitude, that appeared to be oriented vertically due to the ground-level perspective from which it was observed and photographed.

[11] At around 5:00 p.m. Pacific Time on Monday, November 8, 2010, a helicopter from the KCBS news station recorded the vapor trail of what was described as a "missile" about 35 miles (56 km) west of Los Angeles, California and somewhat north of Catalina Island.

[21] Scott Diener, the news director at KCBS, stated that the experts interviewed by his station on "Tuesday night and Wednesday morning had leaned toward the missile theory" to explain the vapor plume.

[6] Pentagon spokesman Colonel David Lapan said that any missile test in the area was "implausible" due to the close proximity of the sighting to Los Angeles International Airport.

[29]As reported on November 10 by CNN, an unnamed official from the U.S. Northern Command stated the vapor trail may have been caused by a plane, and likened it to observers mistaking the New Year's Eve contrail for a missile.

In a November 14, 2010 article, the New York Times quoted Theodore A. Postol, a former Pentagon science adviser and professor at the Massachusetts Institute of Technology, who stated that while he inclined to the jet explanation, he could not "rule out a missile launch.

[32] In the November 14 New York Times article, several days after the event, the incident was cast as an example of how news outlets can be "captives of their sources" and irresponsibly push unproven theses; it was also interpreted as a lesson in the importance of exploring alternative hypotheses.

[6] Federal and military authorities in the United States also faced criticism in the aftermath of the event, particularly for the "inconclusive" nature of the answers provided to the public, and a perceived delay in resolving the issue.

[38] Aviation Week Network reported on the briefing, describing how Rubin used "the November 2010 'mystery missile launch' seen from California" as an example of foreshortened perspective, to illustrate how observers can mistake the direction that a rocket is traveling.