The next thing you know, someone would post here about how evil it was that a TSO photographed them.

OP - I think SATTSO is absolutely correct here - I have never had a problem taking whole fruits/vegetables through security. Definitely take it out of your bag and put it in a separate bin - if they decide to do a secondary screening of the pumpkin, you don't really want them pawing through everything else in your carry-on.

As far as AA, I would say that if you are not on an Eagle flight, you will probably be OK. You should easily be able to fit the pumpkin under the seat in front of you. Tell them it's your 'personal item'. Or get a letter from a mental health professional saying it's an emotional support pumpkin.