美國國內線搭機指南：TSA 安檢、託運行李費 ($35–$45) 與轉機提取行李規則

Checked Baggage Fees ($35–$45) are Never Included in Standard Economy

On nearly all U.S. domestic flights (Delta, United, American, JetBlue, Alaska), standard Economy and Basic Economy tickets include 1 carry-on roller bag (22 × 14 × 9 inches / 56 × 36 × 23 cm) plus 1 personal item, while the first checked bag (up to 50 lbs / 23 kg) costs $35 to $45 each way. Watch out for United Airlines Basic Economy on domestic routes, which restricts you to 1 small under-seat personal item unless flying across the Atlantic/Pacific.

International-to-Domestic Layovers: Always Re-Claim Your Bag at Port of Entry

Unlike intra-European flights, every traveler landing in the United States from abroad MUST clear U.S. Customs (CBP) and physically collect their checked suitcase at their very first U.S. arrival airport—even if the bag is tagged all the way to your final U.S. city. Immediately after walking past the customs exit door, drop your tagged bag onto the 'Connecting Flights Bag Drop' belt and go through TSA security.

TSA Security, Shoes/Liquids (3-1-1) & Passports

International travelers use their valid foreign passport at TSA checkpoints (the U.S. REAL ID driver's license rule applies only to U.S. state IDs). Unless you have TSA PreCheck, remove shoes, belts, laptops, and 3-1-1 liquids bags (containers up to 3.4 oz / 100 mL inside a 1-quart zip bag) at standard TSA lanes, though newer 3D CT scanners at JFK, LAX, ORD, and ATL increasingly allow electronics to stay inside your bag.

Key Takeaways & US Travel Tips

• Verify current entry rules on official U.S. government portals (esta.cbp.dhs.gov, nps.gov, recreation.gov).
• Use our interactive US Sales Tax & Tipping Calculator ($), National Parks Pass Calculator ($80), and Amtrak Rail Calculator.
• Save offline maps and our printable American English & Dietary Allergy Show-Cards before departure.