It depends on the operating airline. Southwest permits power-bank use while it stays visible. Cathay Pacific prohibits using one onboard or recharging it from in-seat power. Both prohibit overhead storage.
| Rule | Southwest | Cathay Pacific |
|---|---|---|
| Use onboard | Allowed while the bank is visible | Prohibited |
| Recharge bank from seat power | Not allowed | Not allowed |
| Storage and carry limit | One up to 100 Wh; personal item under seat, not overhead | Maximum two; under-seat bag, not overhead |
Carry it in the cabin
The FAA baseline is to carry power banks in carry-on baggage, not checked baggage. That carriage rule does not grant permission to use a bank during a flight; the operating airline can set additional onboard rules.
Southwest limits each passenger to one power bank; that count limit took effect April 20, 2026. Its current rules cap capacity at 100 Wh. Keep it visible while using it, do not recharge the bank from seat power, and store it in a personal item under the seat rather than in an overhead bin.
Check use and storage for each carrier
Cathay Pacific prohibits using a power bank onboard and recharging it from in-seat power. Its policy also says not to place it in an overhead compartment: keep it in an under-seat bag, with a maximum of two power banks. The Cathay limit stated here is a count, not a capacity comparison.
A trip with a connection may have different operating carriers. Check each carrier’s current policy before departure; a rule for one airline is not a universal rule for every airline. Charge the device you need before boarding, and keep the bank where you can reach it.
Before boarding
- Verify the operating carrier for each flight, including connections.
- Charge the device you plan to use before boarding.
- When not in use, keep the power bank accessible in an under-seat bag; follow crew instructions.
Sources & scope
- Southwest: Traveling with lithium batteries, e-cigarettes, and lighters ↗
- Cathay Pacific: Lithium batteries ↗
- FAA: PackSafe – Airline passengers and batteries ↗
Reviewed 2026-11-01. Airline policies can change; verify the operating carrier’s rules before travel.