Skule 20

Fjällräven Skule 20 is my bag for this kind of stuff. Been with me in many countries, and also with budget airlines under the seat. Seems to check all your requirements. Also some good color choices imo.

I have three backpacks, for all of them my favorite things are, for Farpoint 40: Comfortable to wear even at 10kg total weight. It's an old version that's a fair bit lighter (I measured mine at 1370g). Fjällräven Skule 20 (latest one I bought and current favorite): It's incredibly light at measured

I recently bought a Fjällräven Skule 20 for a trip this summer and it became my go to backpack in the city. Not sure if you're from the US and the brand is known there, but it's a Swedish brand that's very well known in Europe. Their most famous backpack is the Kanken model, but I find this one much