Tips for finding adjacent airline seats without paying extra

Airlines are reserving a growing number of seats for elite customers or those willing to shell out more money.

The catch: setting these seats aside leaves fewer places for other passengers to sit without paying extra.

Airlines say their gate agents try to help family members without adjacent seats sit together, especially people flying with small children.

Last July, U.S. airlines sold a record 87.8 percent of seats on domestic flights, according to the Bureau of Transportation Statics.

Sometimes plane types are switched between booking and departure — say from a 737 to a 757 — meaning there's a whole new seat layout.

[...] if you booked through Expedia, Orbitz, Priceline or other third-party travel agents, your assignment might not have been recorded correctly with the airline.

ExpertFlyer.com offers free notifications when a window or aisle seat becomes vacant for up to one flight at a time.

— If all else fails, offer nearby passengers candy or a drink to switch seats.

— 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.