Most airlines require you to hand-carry the batteries at the very least. Check with the airlines as they all have their own requirements/restrictions.
Given how luggage is tossed around in the cargo-hold, I would personally recommend you treat your drone like camera equipment and hand-carry. I have done this on several international and domestic flights without issue. If you have to pay extra to check other luggage, do it. consider it "Drone insurance".
In addition to the Karma backpack as your carry-on, You may also wish to consider what other items you will need to take with you on day-trips. You might consider investing in a day-pack that can not only hold your drone, but also hold water, snacks, other camera accessories, sunscreen, umbrella, essentials, etc. You can throw the standard backpack in your checked luggage, and it won't take up much space. Karma has branded gear, but a standard sized backpack can do the job just fine. keep in mind that a higher end pack might be more protective and more comfortable depending on your personal preference/budget.
I'm headed out on a short domestic trip this weekend, and will likely use a $30 backpack I purchased at Costco to carry all my gear. I will carry it on the plane and either store it under my seat, or pack it back into my carry-on once I get through security.
