The ones that I have pictures of are F6F-3K and F6F-5K Grumman Hellcats. These were used to test radio-active clouds during the Bikini Lagoon atom bomb test blasts.They were also used as highly visible drone-controllers for radio-controlled flying bombs (war-weary aircraft packed with explosives), planned for use in the cancelled invasion of Japan. Some were all red, some red w/ yellow tails, some all yellow. Some have the red bar in the national insignia, some don't. This shows they operated from at least 1945 - '47. They can be found in Airpower magazine, Sept. '97. It may be available in back issue, if you are interested. Hope this helps . . .you weren't seeing things ! Pix.