Most airlines allow carry-on luggage that measures up to a maximum of 22 x 14 x 9 inches. In terms of volume, backpacks that are 40-45 liters are good as a carry-on. Anything bigger than that might require you to have it checked in instead.

Are rucksacks allowed as cabin luggage?

Many rucksacks are too big to take into the cabin, so get a bag which is compliant with whichever airline you fly. It doesn't matter what sort of bag you will use, cabin baggage can be smaller items like backpacks, duffel bags, purses, or small briefcases/suitcases...

Can you fly with a rucksack?

Packing a Carry-On Backpack

Like any carry-on luggage, liquids carried in the cabin of a plane in a backpack are subject to the 3-1-1 rule. That means you can take as many 3.4-ounce or smaller bottles that fit inside a single clear 1-quart baggie.