I took a break from JSVB this month, and the reason was a quick vacation to Las Vegas, USA.
One thing I wanted to do in Vegas was to spot the movements of the mysterious black-ops JANET flights which originate from a private, high-security terminal annexed to McCarran International Airport. Not five minutes into our cab ride to the massive and outrageous Caesar's Palace, an almost non-descript JANET airliner flew final approach over the highway, prompting our friendly Russian driver to launch into his own theory of Roswell, UFO's, and high-level government conspiracy. At that moment, I knew our vacation was going to be a great one!
"JANET" is reportedly the call sign for a number of airliners possibly operated by EG&G, a defense contractor that may or may not be owned by government services megacorporation URS. The JANET craft are typically painted pure white with a long red stripe over the windows across the fuselage. The JANET fleet is supposed by conspiracy theorists to be used as commuter craft for thousands of top-secret workers who live in the Las Vegas area but work in facilities such as Groom Lake/Area 51. JANET has its own air terminal which is guarded heavily against trespassers and the general public. Presumably you could watch some of the action on the JANET jetway from the comfort of the nearby Luxor Hotel, provided you had the use of a good telephoto lens.
The Internet suggests that the US spends upwards of $56 billion a year on so-called "black" operations, ranging from secret military missions to clandestine arms research. With such a massive amount of money at their disposal, I can imagine that running JANET as a top-secret airline operating in the open would only use a small fraction of this budget. Even so, only Russian cab drivers seem willing to offer any accountability.
You can try using Internet resources to track the various JANET flights, some of which are regular shuttle flights from Vegas to who-knows-where, while others fly flight plans that are completely conjectural. Maybe someone at the URS head office wanted to see Donny & Marie at the Flamingo Showroom? When you run your own private secret airline, you get to fly it however you like.
Nobody can definitely say what "JANET" stands for.