American Airlines and Bikes.
 

I have a domestic flight soon (Phila to Seattle) and I plan on taking my bike. I have done a few bike forum searches but thought I'd give details and get current information from our expert fellow bike forum travelers. I'll be flying AA. Outbound in 1st class, back is in coach. I have the Oracase ninja and have packed it before for long car travels to save space. This will be the first time it takes flight. I recently added the frame protection kit they sell and will be using that for the first time. My bike has Sram Red e-tap. From what I gathered I'll remove the batteries and put in carry-on. How about CO2 cartridges? Leave at home? Buy locally? I do like the idea I read here about leaving a note to TSA etc.
Any current tips and advice greatly appreciated. Thanks!

Have you considered Bikeship instead? I haven't put a bike on a plane in some years but the experience of going from Las Vegas to Minneapolis was so ugly that I vowed never again to do that. With Covid19 and the surge in passenger numbers it can only be worse these days. You have the hassle of taking luggage + the bike box to the airport, lugging it around the airport, and then dealing with the ass*****s who run the airlines (Delta I think). Mine was not a direct flight and even though we did not change planes they decided to charge me an extra fee for every time the plane set down in an airport. The other reason I would do it this way is no hassle with transporting the bike. It is there at your destination when you arrive and can be held at a FedEx office for 5 days if there are compilations with the timing. https://www.shipbikes.com

Batteries in your carry-on, including any in the bike computer/lights. CO2 cartridges are not allowed on the plane so leave them at home. If you need to buy them at your destination.

Always remove the eTap batteries when transporting the bike. eTap will sense movement and be active, so they'll arrive dead.

Any compressed gas is a major no no.

Interesting. So when you ride does it automatically a activate and then turn off when, say, the bike is sitting at home?