This is yet another reason why I love JetBlue! Check out their carry on limits:
Each customer may bring one bag that fits in the overhead bin plus one personal
item (purse, briefcase, laptop, etc.) that fits under the seat in front of you. Your
personal item must not exceed 18"l x 15"w x 8"h in order to fit under the seat in
front of you.
To fit in the overhead bin, your item must not exceed:
for our Airbus A320: 26 inches length x 18 inches width x 12 inches height
for our EMBRAER 190: 24 inches length x 16 inches width x 10 inches height
If you have a medical assistance item, it will not count as a carryon.
We fly with 2 kids and we only have carryons! One each and we have never had a problem finding luggage that is the correct size. We ship all our toiletries down ahead of time. I would not bring a carryon that is even a half an inch bigger! They will count the wheels and handle if it sticks out. I would just check the bags or go buy bags that is the size your airline allows. Could you imagine the hassel you could cause yourself at the airport!?