Typically in economy, you can bring one carry-on and one personal item. If you bring two bags, one must fit underneath your seat and the other can go into the overhead bin. If you're flying in an upgraded class like business or first, you may be allowed an additional carry-on bag.

Whether you can take two carry-on bags depends entirely on the airline's "Personal Item" vs. "Carry-on Bag" definitions. Standard legacy carriers (like Delta, United, or American) typically allow one carry-on bag (to be stored in the overhead bin) and one personal item (like a purse, laptop bag, or small backpack to be stored under the seat in front of you). This effectively gives you "two bags," but the second must be small. However, "Ultra-Low-Cost Carriers" (ULCCs) like Spirit, Frontier, or Ryanair have much stricter rules. Their basic fares often only include a single "personal item." If you bring a standard-sized carry-on bag (the "second bag"), you must pay a significant fee, often $50 or more. Furthermore, if you are traveling on a "Basic Economy" ticket with a major airline, you may be restricted to only a personal item, with no overhead bin access permitted. Always check the specific "dimensions" listed on your airline's website; in 2026, many airlines use "sizing boxes" at the gate to ensure that your "personal item" isn't actually a disguised second carry-on, which could lead to an expensive gate-check fee.