Just wondering what the best way is to travel with the P4 without hassle at the airport? I live in Canada and I'm traveling to the US.  Is the large lithium battery going to be a issue?

Hello adkornelsen, I'd suggest you to get in touch with your airlines in order to get the regulations. What's more ,here is a tip of carrying batteries onto the plane:

DJI-Paladin Posted at 2016-6-28 14:09
Hello adkornelsen, I'd suggest you to get in touch with your airlines in order to get the regulation ...

This is not true.
No airline in the world asks you to discharge your battery.
No airport security people will ever check the discharge level.

It's only an IATA requirement for shipping lithium batteries as cargo but does not apply to passengers with a small number of batteroes in their carry-on luggage.

You'll have no hassle at the airport as long as you put your batteries in your carry-on luggage.
Go to your airline's website and search for batteries to see their requirements.

Don't worry, it's easy and hassle free.