You’re not alone. A similar occurrence was reported in Jacksonville, Florida. Unfortunately, reportage quickly turns into conspiracy fodder. We took your query straight to Nellis Air Force Base. There, a Sgt. Hubenthal informed us that "Flying close is something trained pilots are trained to do and able to," sounding unfazed about the touching-wingtips sighting. He then referred us further up the chain of command, which was unresponsive (we did speak with one human, who simply laughed when we read him your question). And that was the last we heard from the U.S. Air Force.
The "Janet" (Just Another Non-Existent Terminal?) fleet, that transports military and civilian workers to the Nevada National Security Site, comprises a fleet of six Boeing 737-600s, painted white with a prominent red cheatline, so it wasn’t one of those that you spotted (see QoD 11/19/2012).
Of course, Area 51 -- that small supersecret area within the Nellis Air Force Bombing and Gunnery Range referred to as ’Dreamland’ on aviation frequencies -- is alleged to be the testing ground for the latest generation of secret military aircraft, and is believed to have hosted such secretive programs as U-2, F-104, SR-71, and F-117A and the F-22 before they were introduced to the public. It’s said to be the testing ground for the hypersonic stealth aircraft project/myth (depending on your point of view on such things) known as Aurora, not to mention the location of ongoing research and storage of recovered extra-terrestrial craft and bodies.
Unfortunately, no one has yet been able to prove or confirm any one of these rumors and conspiracy theories, although many individuals have reportedly seen aircraft of anomalous design and/or capabilities leaving the base, particularly at night. Claimants report sightings of aircraft that are able to accelerate at amazing speed and make rapid changes in direction - far beyond any terrestrial technology currently known or employed.
Without photographic evidence, however, we’re afraid your query, like all the others of its ilk, is doomed to remain a mystery.