Hello Sittoss1930. Your question is valid but not really in this dicussion thread.
If you want to start a discussion about suitable hand luggage, please search the forum first. Also, do check the website of the airline you intend to use - they all list the maximum size of hand luggage that they permit.
Fitting them into the overhead bin is not the problem - if you buy a case that fits the maximum size allowed - then it will fit in the bin.
You are welcome to ask more questions and start a new thread if you want.