We list only official government resources which are the most up-to-date and reliable sources of information.
TSA: traveler's starting point to get information related to air travel, road travel (official website of the Dept. of Homeland Security)
Air travelers: check out this sub section: Liquid Rules: 3-1-1 for Carry-Ons, Prohibited Items, Acceptable Identification at the Checkpoint, Safe Travel with Batteries & Devices, "Checkpoint Friendly" Laptop Bags, Special Items, Baggage Locks, Travelers with Disabilities and Medical Conditions, Traveling with Children, Wait Times, Customer Service
TSA: air travel (official website of the Dept. of Homeland Security)
Very interesting is the following TSA web page which provides specific information about the air travel experience regarding dressing, laptop bags, removing shoes, the screening process, and more...
TSA: air travel: screening process (official website of the Dept. of Homeland Security)
The CBP covers many topics in detailed articles, e.g.
Travel Smart: Bringing Food into the U.S., Clearing CBP, Electronic System for Travel Authorization, Global Entry Program, I-94 and I-94W, Know Before You Go, Restricted/Prohibited Goods, State Department International Travel Information, Tip: Register Items Before You Leave The United States, U.S. Customs and Border Protection Policy Regarding Border Search of Information (pdf - 161 KB.)
APIS: Advance Passenger Information System, Arrival Procedures for Students and Exchange Visitors (doc - 36 KB.), Currency Reporting FinCen 105, eAPIS Information, Issuance of a Visa and Authorization for Temporary Admission into the United States for Certain Non-Immigrant Aliens Infected with HIV Final Rule, Locate a Port Of Entry - Air, Land, or Sea, NSEERS, Travel Publications, U.S. Visitor and Immigrant Status Indicator Technology (U.S. VISIT), User Fee Decals and Transponders, Visa Waiver Program
IF THOSE INFORMATION ARE OF INTEREST FOR YOU then visit following CBP page and find your way from there: CBP information for travelers (official website of the CBP)