One of the best investments I ever made was the original Patagonia MLC wheelie. It stands for Maximum Legal Carry-on. They have a black hole version now which I am not familiar with but I assume is the same quality / usefulness. I had a few jobs where I commuted regularly on CRJ 200's and this bag fits in the overhead with no issue. The ability to pop out the straps and wear it like a backpack makes the gate agents much less concerned about the size.