Go through your results for flights to Flint in the USA with Netflights. The most popular airlines for this route are British Airways & Qatar Airways, with British Airways claiming the top spot. Although Air France usually has the best prices, it's best to double check what's available for your travel dates.
Flexible on dates? Conducting your search by month allows you to compare prices to Flint throughout the year. Accommodation prices will also be higher at this time of year.
Flint receives 21 direct and indirect flights every week, but the cheapest airline is normally Air France. So, if the flights to Flint don't work for you, you could always try searching for flights to other airports in the USA.
Looking at a few different departure airports will give you even more choice. See what you can find. And remember, it's best to book your flights in advance wherever possible.