Field Guide · Airport security & carry-on

Security and What You Can Carry On

By Rachel Julian, Editor-in-Chief · July 21, 2026 · 4 min read

The rules that get you pulled aside are the ones worth knowing cold. Here’s the plain guide to liquids, laptops, and what flies in a carry-on — straight from TSA.

Direct answer: A smooth security line is mostly knowing the rules before you’re in it. Here’s the plain version, sourced to TSA — because the rules do change, so the links are the last word.

A smooth security line is mostly knowing the rules before you’re in it. Here’s the plain version, sourced to TSA — because the rules do change, so the links are the last word.

General information — rules and policies change. Confirm current specifics with the relevant authority (your company, the airline, the government) or a professional. Where a public rule applies, its primary source is linked.

Can I bring my work laptop through airport security?

Yes — laptops fly in carry-ons. At standard screening you take it out into its own bin; with TSA PreCheck it stays in the bag. Keep it accessible so the line moves. Source: TSA — what can I bring ↗.

Can my company pay for TSA PreCheck?

Often yes — many companies reimburse PreCheck or Global Entry as a travel benefit, and some credit cards cover it. Check your policy; it’s a small cost that saves real time for a frequent traveler. Source: TSA PreCheck ↗.

Can I bring a full-size toothpaste on a plane?

Not in your carry-on — toothpaste counts as a liquid/gel/paste, so it must be 3.4 oz (100 mL) or smaller to pass security. A full-size tube has to be checked, or just buy travel-size. Source: TSA — liquids rule ↗.

Can I bring a razor in my carry-on?

Disposable and cartridge razors are fine in a carry-on; safety razors are allowed but you have to remove the blade; and straight razors and loose blades have to go in checked luggage. Source: TSA — what can I bring ↗.

How do I pack liquids for a flight?

Follow the TSA 3-1-1 rule: containers of 3.4 oz (100 mL) or less, all fitting in a single quart-size bag, one bag per passenger. Anything larger goes in checked luggage. Source: TSA — liquids rule ↗.

What size bag fits under the seat?

Your “personal item” — but the exact dimensions vary by airline (roughly 18×14×8 inches on many carriers, smaller on budget ones), so check your airline’s limit. The under-seat bag is the one that’s always with you.

More answers for the road in the Field Guide.

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The Field Guide is The Sales Traveler’s own editorial — experienced-traveler judgment, on the traveler’s side. Where an answer touches a rule or number (policy, tax, security), confirm it with the primary source; we don’t invent specifics. Independent and reader-funded; no paid placements.