Basic economy carry-on rules: United vs American

This is where the two airlines differ:

• American Basic Economy generally includes a standard carry-on bag.
• United Basic Economy on many domestic flights allows only a personal item that fits under the seat, with a full-size carry-on costing extra.
• Checked bags cost more on Basic fares, especially on American after May 2026.
• Rules change, so check the fare details before you buy.

Compare the total cost with a bag included, since the cheapest fare isn’t always the cheapest trip. More on United vs American baggage fees is here.