Different airlines have slightly different rules, for example, when it comes to basic economy. None let flyers pick a seat in advance, but Delta allows overhead bin space for basic economy travelers. United and American don't allow fliers in this class to carry more than one small personal item onboard, unless they are frequent flyers or have the airline's credit card. Carry-on limitations that force travelers to check a bag and pay a fee — even if their bag is checked at the gate — may cancel out the savings associated with a basic economy ticket.