I can out of shoprite after food shopping and the sky was a perfect blue no clouds and about a half an hour from sun set, and i noticed two large twin engine jet air craft about the size of an airbus 300. what caught my attention was how close these jets were flying in proximity to each other, they were both flying around 18000 to 24000ft in altitude and roughly around 1/2 of each other, no further than that! both jets were gave off a heavy contrails and you could clearly make out the shape of the jets and their wing shape and their engines , what was very odd was this objet that was pacing both jets and flying in a direct path due south their was a lead plane followed by the objected and than the second jet directly behind the object. the object appeared to be about a 1/4 of the size of the jets and gave off no contrail what so ever, which struck me as odd being they were all flying at the same speed same altitude and the same direction, the object and the trailing plane all appeared to be following the lead plane, when first spotted the object between the planes seemed to be like a light lead colored as it moved along with the planes it seemed to change to a bright light pulsating at uneven intervals, again no contrails from this object, it perfectly paced the jets and i watched the two jets and the object for about 4 minutes were i estimate that they were around 15 miles+ away from me flying due south form my location and around 10 to 20 miles west of nyc at that time. just to be clear each jet gave off a reflection of the sunlight but the object that was following them was at least 3 times brighter than the jets at it's demist point and about 7 to 10 times brighter at it's brightest point when pulsating. i have to say it was very odd i've seen a lot of plane but have never seen anything like this before . i observe this from directly below to watching it move off into the horizon with both jets.