What Are Those Lights in the Sky?
Of all the reports that stream in to police and UFO investigators, most end up being merely a misidentification by the witness of the various running and operational lights on conventional airplanes. While the average person can easily identify a commercial aircraft's running lights under normal circumstances, sometimes weather or an odd angle of approach will give the illusion of strangeness that is all that's needed to let the imagination of the believer run wild. It is crucial that those interested in watching the sky for intruding, possibly alien, craft educate themselves on the standard patterns of aircraft lighting to minimize the wasted time and energy of investigating cases of mistaken identity.
Many of these standard features can be easily noted when the plane is flying low, especially when nearing a runway. If you want to look for UFO's at night, a good pair of binoculars will help prevent many mistakes. The red and green wingtip flashing lights are standard on most aircraft. There are also white and red strobe lights on both the top and bottom of the craft that are supposed to stay on from engine start to chocking after it lands. These are, however, sometimes turned off in cloudy conditions as the reflection and glare off clouds can be a distraction for the pilots.
Landing lights are turned on at 10,000 feet whether it is nearing an airport or just reducing altitude for whatever reason. This can make an otherwise dim looking lighted object suddenly flare up in intensity as it is equivalent to suddenly turning on the headlights at the bright setting in an automobile. These bright lights are on during takeoff as well and are turned off when the airplane reaches the 10,000 foot mark. In foggy or dusty air this can illuminate the lights to appear the craft is shooting "beams" out in front of it. Additional taxi lights come on when the landing gear are deployed. Some commercial jetliners also have a pilot operated control that adjusts the brightness on one side or the other. Most commercial jetliners also leave the "logo" lights on the tail to clearly expose their company name for identification although some companies turn them off after takeoff.

Boeing 737 showing common types of lights placed on aircraft.
Photo credit www.aerospaceweb.org
Helicopters always carry at least one bright white light on the belly and generally the red strobe on the tail section. While many helicopters do not muffle their engine sound and can be heard for miles, this is not universal. Not only do some provide quiet running engines and wider, sound depressing rotors, many military helicopters have extra stealth approach technology to keep them unheard until they are almost on top of you. Military craft also use fewer lights during on-duty operation which makes them harder to spot. Since helicopters are, by nature, very maneuverable, they can change direction swiftly as well as hover.
Because normal aircraft are subject to the same kinds of style variations as automobiles, even the standard light placement has its variations. For a serious amateur ufologist, time spent near a busy airport at night, both commercial and as close as you can to military ones, can slowly grant you familiarity with the light patterns you can dismiss as terrestrial. This way you will be much more likely to be able to pick up on and better report those instances when the lights you see in the sky are definitely not conforming to any pattern or standard behavior.
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