Pensacola International Airport (PNS), Louis Armstrong New Orleans International Airport (MSY)
Unfortunately there is no good airport option for Hangout. Pensacola is the closest airport, but it's also a small airport and thus get's expensive quickly for Hangout's dates. It's also still an hour+ away from Hangout Fest. You can fly into New Orleans , but then you have about a 3 hour drive. If you can afford Pensacola I would go that route, but be sure to book early.
Your rental car price as there's no great public transportation or shuttle to use for Hangout.
Generally the cheapest time to book flights for Hangout Music Festival will be about six weeks before Hangout Music Festival. This means you should be focused on booking your flight in April 6, 2018. This may seem late to you planners out there, but statistically it's the cheapest time to book flights. That said, if this is too late for you book it earlier. One final note is that plane tickets for Hangout Music Festival tend to skyrocket about two weeks out, so certainly don't wait that long to book a Hangout Music Festival flight.