On the morning of December 8th, 2019 between 6:30 a.m. and 6:40 a.m. unusual sky phenomena were spotted by my sister over the sky of San Marino.
She described the phenomenon as shown in the following picture.
That these planes were probably excluded because they did not blink. It could of course have been a series of satellites that were just launched into orbit on their mission. However, this can also be excluded, since no demonstrably larger mission has taken place, neither from SpaceX, Blue Origin, nor from Nasa itself.
Presumably it could also have been a maneuver by satellites currently orbiting the earth. However, the satellites would then have to be equipped with an electric thrust drive, which not many satellites are likely to have.
So it remains a mystery to us. If you have an idea, feel free to leave a comment here if you've already read so far. 😉