Frontier Airlines is an American low-cost carrier that operates flights to over 100 destinations across the United States, Mexico, and the Caribbean. If you have booked a flight with Frontier Airlines Change Flight but need to make changes to your itinerary, you can easily do so by following the steps outlined below. you will be taken to a page where you can select your new flight. You can search for flights by date, destination, and departure city. Once you have found the flight you want, select it and click on the "Continue" button.