Does Ryanair allow rucksacks? My rucksack when empty measures 55cm*40cm*20 cm (I measured with a tape). Is it possible to squish it to carry on Ryanair if it is just half filled ?
Ryanair answers your question:
What you CAN bring on board
If you have purchased "Priority & 2 cabin bags" or a Plus/Flexi ticket you can carry the following on-board:
One small bag e.g. handbag, laptop bag etc. not exceeding 35cm x 20cm x 20cm
One cabin bag, not exceeding 55cm x 40cm x 20cm in size and 10kg in weight.
If you have not purchased "Priority & 2 cabin bags" or a Plus/Flexi ticket you can carry the following on-board:
1 small bag on board (35cm x 20cm x 20cm)
If a second cabin bag (55cm x 40cm x 20cm) is brought to the gate, it will be put in the aircraft hold free of charge. The Regulations on Cabin Baggage apply.
Yes, Ryanair allows rucksacks. Yes, you can bring your rucksack on board. It may be put in the aircraft hold though.
Neusser is right. You can bring it and since rucksacks are easily "moldable" you shouldn't have problems. However due to the new regulations he mentioned be prepared to the eventuality of having to send it down in the aircraft hold.
From my personal experience, attendants checking luggage sizes never bother with backpacks, they go after trolleys and hard case luggage to see if they fit in the measures. I saw on many occasions (even after the new regulations) people with huge travelers backpack in the cabin.
Long story short: don't worry, one way or another you will be able to transport your rucksack for free.