I will add: All of the airlines I've traveled on (no Mexican ones!) allow for two carry-ons at no charge, but I usually have three - my two cookie containers and my computer bag. Fortunately, the two cookie containers are very compact and snap together. So when I am getting on the plane, I have them snapped together (I slip the extra lid in my computer bag) so it appears as if I have two carry-ons. When I get on the plane, I un-snap the cookie containers, put the extra lid back on one of them (so both are now separate and lidded) - and effectively turn my two carry-ons back into three. One cookie container can fit under the seat in front of me (on most every plane except for puddle-jumpers); the other (along with computer bag) either takes up part of the person's area near me (if they oblige) or goes into the overhead compartment.
Sometimes I don't even bother to conceal my third carry-on though, and I've gotten on - or gate-checked my computer bag without my computer and wallet in it. I've never had cookies confiscated or had to leave them behind. I usually travel with anywhere from 75 to 150 cookies as well.
Hope this helps.