One caution about flying with your Phantom, if you fly on a smaller regional jet, the kind that have two seats per side, some of them don't have enough overhead room for the standard carry-on of 22X14X9', which is the approximate size of many Phantom backpacks. Also, prop planes, often used in rural areas, they don't have adequate overhead space either. They will typically collect those 22X14X9 carry-on bags right before you board the plane on the tarmac and put them in the belly of the plane. When you land, you usually pick them up on the tarmac too, so the handling isn't as much as going through baggage claim.
It's those times you need to be prepared to pull the batteries out of the backpack quickly, putting them in a smaller bag as a very small carry-on that fits in the smaller overhead, or under the seat. Hopefully your drone won't get damaged with this "jetway/tarmac bag collection" process. It's those scenarios where the hard shell backpack that DJI sells (and others) that might be worth using. I personally don't like those due to the limited storage room inside, but the hard shell protection, while being light and backpackable is a good way to go if you fly those types of planes all the time. Check your flight reservation carefully, study the plane type, be prepared.
