Cheers guys - I'd say the flame lantern idea works for me. If they were in fact a lot lower than I initially guessed (say only a few hundred feet) then my original speed estimate would have been well over the actual speed. My S.O. said they looked like something flaming and guessed at a balloon, which I ridiculed at the time but maybe she was closer to the mark than me (and/or better eyesight...)
Thanks!
WCB