M.B.
I think the trigger is that he's 2 and gets attention from the tantrums. When my kids were 2, they often didn't like new things. A hayride would have been hit or miss in this house. In fact, I sat out of my family hayride this year with my 20 month old b/c he cried when he was lifted into the wagon. I'd treat most of them very matter of factly and not fight him on them (i.e. wearing his costume). Don't try to console him or talk him into going too much either; by the time they are throwing a tantrum, they can't even process what you're saying. Take him out of the situation and let him cool off on his own. Then tell him "if you don't like something tell Mommy, but you are not to act like that again - got it? You tell me 'Mom, I don't like it'" Give him the exact wording and have him repeat it. Or use a sign of some sort to communicate with you. He'll get it -- eventually!