Same day flight modification fees that are usually set at JetBlue Airlines range from $25 to $200 is mostly owing to the type of fare used. But If you make changes on this category based on the JetBlue Same Day Flight Change policy, one can save a few hundreds of dollars. For instance, passengers who are Mosaic members of JetBlue do not incur any fee at all when they want to change their flights. Thus when you are planning a flight and you making the booking of your seats with the jet blue airline then you can try doing it through the membership.