42 Liter Pack?

I'm sorry, I did use the search but it's not very advanced and plus I'd like a little firsthand advice on pack sizes (yes, probably been asked many times).

Is a 42 Liter backpack a good size for me for a two month trip in summer to SE Asia? (I'm a gal, and was fine with a 65L+10 pack to South America for 2 months in winter, carrying warm clothes and a sleeping bag if that's any indication). Would 42 liters be small enough to carry-on a bus or plane? I would like to pack light, easy to carry, but don't want to be stuck with somthing too small either. Here is the one I am thinking of: Deuter Futura 42 Pack

Thanks!