Frontier Airlines encourages online check-in up to 24 hours before departure to save time. If you need assistance or are checking luggage, head to the airline’s dedicated counter in the main check-in hall of Terminal D. Friendly staff will guide you through baggage policies and any optional services you might need, such as seat upgrades or extra legroom. https://airportsterminalhub.com/airlines/frontier-airlines/frontier-airlines-dallas-fort-worth-international-airport-dfw-terminal/