strange sighting last night over london at approximately 2130 hrs flying north east static red light on a unknown craft observed flying over me maybe 20 thousand feet no navigation lights just a static red light i watched this until it faded out of view approximately 1 minute later a grey object with no lights flew in the same direction as the red light very fast not making any obvious noise. i could see the outline appeared to be oval shaped. i checked flight tracker for the time and location but nothing was shown. this may have been a possible stealth aircraft unknown if this was linked to the previous red lighted object but was travelling in the same route as it. did some searches on static red light aircraft but nothing came up as planes have to have flashing beacons. was not a drone. this sighting was on a busy flight path to london heathrow very strange how the static red light craft and another craft with no lights were flying over london. estimated size of first object with red light would be the size of a mid size aircarft,second object with no lights was larger and traveling faster possible the size of a a380. i think the aircraft with the static red light was possibly an escort for the stealth craft which was traveling with no lights ?