Originally Posted by bbtrvl

Lots of stories of people carrying on watermelons, so I would think it's ok. If the TSO insists, you might have to trash it, but usually they do not consider that sort of thing a liquid.

To avoid hassle, you probably want to take them out and tray them, or at least carry them in an entire separate bag.

If you are going to an agriculturally sensitive state like HI, FL or CA they may be confiscated for non airplane related reasons, so don't take them to those states.