Go through your results for flights to Dubois in the USA with Netflights.
If you don’t have set dates for when you want to fly to Dubois, try searching by month – that way, you can compare airfares throughout the year.
So, if the flights to Dubois don't work for you, you could always try searching for flights to other airports in the USA.
You can also broaden your search by looking at more than one departure airport. Have a look around – you might be able to save by flying from a different airport or city.