In this and in that are similarities.
I can remember two formations of three objects - as I wrote - the leader and the two wingman.
There were also two independent - separate objects, of one I followed.
Before vanishing "in thin air" - the body of the object was shining, as sun reflecting from a steel - then transforming to black before vanishing.
When I noticed those it appeared first to be a flock of birds circulating a round, in 8 form going up and down as mosquitoes. Some of those were flying anticlockwise other clockwise in same spot before departing. One set of three objects more to North, other to West and one set to South. The single one that I followed headed to South-Est.