A proud father loses his Crop Dusting business after 09/11 shutdowns, and addiction threatens his dignity; his only redemption may cost him his life as stealing his repoed plane could do more than break the bank.

The idea is solid. But perhaps you should use the savings and loan scandal instead of 9/11.

The idea is that the greedy banker shut down the lead character's business in spite of the fact the banker, who broke the law, got bailed out and is still living in a mansion.
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"When a salt of the earth crop duster is victimized by the savings and loan scandal, he must steal back his impounded plane to get revenge on the greedy bank CEO who foreclosed his business in spite of being bailed out himself."
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I know that example was a little long but I hope you get the idea.

Good luck with this, I think it's a solid premise with possibilities.

While contemplating the goal, this controversial what-if popped in my head:
A father becomes disillusioned with the American Dream when the events of 9/11 cause his crop-dusting business to fold – so he steals back his impounded plane in order to kamikaze attack the mansion of the “too big to fail” bank CEO.

Keep the logline to the main storyline:
Also, you should add a face to the antagonist:

When "This guy" shuts down his business, a crop duster and his wayward son must steal his plane from impound in order to stick it to the government and those who want to steal his freedom!"