IPad functionality in the EU and USA?

All Apple iPad USB power adapters are designed for use with power sources rated to provide 100V AC to 240V AC at 50Hz to 60Hz. Apple iPad USB power adapters also comply with the IEC/UL 60950-1 and IEC/UL 62368-1 standards for use with power sources rated to provide 115V AC at 400Hz (typically found onboard commercial airlines).

While your Power Adapter will be fully usable when travelling internationally, you may require a simple pin-adapter to allow the Power Adapter to be used with AC power outlets in different countries. For example, a US flat 2-pin connector will require an adapter for the standard European round 2-pin socket - or UK 3-pin square socket. The reverse is equally applicable. Travel adapters are readily available.

Excellent point! I admit, I do worry about cheap plug adapters.

All you need is the correct power adapter for the outlets in the country you'll be charging it in. So, when you return to the U.S., you'll need to buy a new adapter.

Glad it helped!

And many of the power adapters work just fine on 110 or 220, you just need an adapter for the plug.