Some American Flying Fortresses were used by the RAF for ground and nightfighter radar jamming at night during Lancaster bombing raids, these operation were very secret and little was known about them until resently. As the Flying Fortresses used by the USAAF were strictly daylight bombers and Lancasters were almost always used for night raids they would not usualy fly together, possibly crossing over the north sea some times. There could be the remote possibility of them operating together on humanitarion supply dropping missions at the very end or just after the end of the war.