American Airlines has introduced some new restrictions regarding lithium batteries and chargers aboard a flight (and it's possible other airlines will follow). Hat tip to Core SWX for letting us know.

You can see the most relevant restrictions below or see the full text on their site here:

Lithium Batteries

Allowed for travel? Yes, with restrictions

Notes:

• Lithium batteries must be carried in carry-on bags only.
• Spare batteries must be individually protected.
• Lithium ion battery limits (by watt hours, Wh):
  • Less than 100 Wh: Up to 4 spare batteries in carry-on
  • 100–160 Wh: Up to 2 spare batteries in carry on
  • 160–300 Wh: Contact Special Assistance before traveling

Portable Chargers (Power Banks)

Allowed for travel? Carry-on – Yes; Checked bags – No

Notes:

•  Limit 2 portable chargers per passenger while onboard
•  Each charger must not exceed 100 watt hours (Wh)

'While onboard:

• Keep portable chargers within reach and visible while in use 
• Store them in an easily accessible place, such as:
  • A personal item under the seat 
  • The seatback pocket 

Do not

•  Use in seat power outlets to recharge portable chargers while onboard 
•  Store portable chargers in overhead bins or other enclosed spaces