In 2026, whether it costs to change your itinerary depends entirely on your fare class. Most major US and European carriers (like Delta, United, and American) have eliminated change fees for Standard Economy and higher tickets on domestic and many international routes. However, a supportive peer "fine print" warning: you still have to pay the fare difference. If your new flight is $100 more expensive, you pay $100. Conversely, if you have a Basic Economy ticket, changes are usually strictly prohibited or come with a heavy penalty (often $99+). Additionally, some "ultra-low-cost" carriers (like Spirit or Ryanair) still charge "modification fees" that can sometimes exceed the price of the original ticket. Always check if your ticket is "Flexible" before you hit the purchase button.