As noted by others, the carry-on is limited by the type of aircraft and thus the nature of the overheads. E145s and CRJ200s cannot accommodate very much overhead so it's pretty much the basics. E175/190s and CRA700s have larger bins but still not large enough (unless you're in F) to accommodate anything larger than 18"-22" roller cases. However, the standard for AE is to gate tag and use the valet service where you drop your larger bag(s) before entering the plane, then wait for the bags before heading into the terminal upon arrival. No charge for this service which is pretty standard to all regional carriers in NAmerica.