Thank you for the question. The answer is "maybe". State Fair is an early season variety, while Frostbite is a late season variety. For cross pollination, you need two apple varieties but for most consistent cross pollination, they should bloom at similar times for bees to cross pollinate. Crabapple trees generally have longer bloom times and will pollinate either of your trees if they are about 100 feet away or closer. The other option is to plant a few other apple trees that bloom about the same time as your trees. It all depends on the year and any overlap in bloom time. This link provides more varieties and bloom times: http://mnhardy.umn.edu/varieties/fruit/apples/all-apple-varieties
Thank you for contacting Extension.