The property seizure was in addition to the fine, not an optional form of punishment.
Had the pilot simply been unable to pay the fine, then seizing and selling his plane (as well as any other assets) may have been justifiable - but only if proceeds beyond the fine were remitted to the plot.
But in this case, asset forfeiture laws meant that the A/C was no longer his to sell . . .
Substute fentanyl for beer and how do you feel about the forfeiture? Beer and other alcohols are just as problematic in some Northern communities. Thiz also sends a strong message to any pilots who might decide to smuggle alcohol in Alaska.