Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Mississippi to Croatia as you normally would.
Due to the rapidly changing circumstances due to COVID-19, airlines like Delta flying from Mississippi to Croatia have implemented new flexible change policies.
Yes, there are multiple flights from Mississippi to Croatia for under $1,100. The cheapest flight booked recently is on Delta for just $1,009, but on average you can expect to pay $1,009.