I flew from Europe into London City recently. Flight was 1.5 hours. Gazing out of the window, (we were just above the clouds), I saw a total of 7 other aircraft at roughly similar height, including one approaching at right angles that climbed steeply above us. None were really in close proximity except the one that climbed. I was a bit unnerved by that one. I don't know what was happening above/ below/ other side. My window was just over the wing so view limited.
Has anybody else seen several other aircraft on a shortish flight?