[Gandalf_The_Gray]

The usual MO for these “frozen meteorites” is they are tidy-bowl blue and smell like poop as they melt. They are almost certainly the result of a malfunctioning drain valve on an airliner's sewerage holding tank. If the 'royal flush' is triggered at sufficient altitude, the discharged glop freezes into a solid poo bomb on the way down.

Regards,
GtG

[xjcsa]

It could also be ice that accumulated on the leading edge surfaces of an airplane climbing through clouds; the ice could have then separated from the plane at a later time. Pieces of ice like that can sometimes be quite large, in the tens of feet long.