As a record number of passengers will fly this summer, here’s a reminder about some of the fees fliers will face.

• Checked bag. Most airlines now charge $25 each way for a checked suitcase. Southwest Airlines and JetBlue Airways do not, although JetBlue is about to start charging for some types of tickets.
• Reservation changes. Airlines charge up to $200 to change a domestic ticket and that is before any difference in fare. International flights cost even more to alter.
• Preferred seats. For short flights, it could cost as little as $9 extra to get a better seat. For long-distance international flights, it could be $300. Typically, passengers pay $25 to $50 more.
• WiFi. Up to $30 a flight. Large discounts are given for purchasing it in advance with Internet provider Gogo selling one-day passes for $16.
• Other common needs. Discount airlines like Spirit, Allegiant and Frontier charge for things most fliers assume are free, like water, carry-on bag and printing a board pass at the airport. Read the fine print before booking.