I had a hard time finding good answers about this before my trip I just took today, so here is some feedback/advice for other users...

I followed the FAA's guidelines for small lithium batteries (less than 100 watt hours each) on this site:
https://www.faa.gov/about/office ... s_and_batteries.pdf

I flew with 3 "spare" batteries in my carry on.  I discharged the batteries the night before my flight as low as possible.  And to be safe for the rule about having to be protected from short circuit, I put each one in a separate Ziploc bag.  I had no issues through security at all.

(I flew with the Seahorse 920 case as a carry-on on Southwest)

If anyone has any other questions about flying with your batteries on an airline, let me know!

Thank you for sharing experience!

so you couldn't find any of the threads discussing carrying batteries on plane sin this forum?  Really?

Just passed in transit at the Prague airport with P3A plus 3 batteries as cabin luggage. The officer only asked if i could remove the battey from the rc. Said rc is off and battery cannot be removed he let me go.