Any problems with the flight attendants wanting to put your bag in the cargo hold because of lack of overhead bin space? Seems like every time I fly now , that's the first thing that happens.
Boarding as early as possible helps. If you are asked to gate check your bag, you just ask nicely if you can have a look for space as you have valuable, sensitive equipment you would rather not put underneath if you can avoid it. Say it nicely and in a way you arent being "its all about me" if you get what I mean. I have learned that Flight Attendants dont like people that think they are the only ones flying that day.

Bringing them a goody bag with M&Ms and Starbursts as a bribe helps immensely as well

I flat out tell them its a bribe to buy me an extra 30 seconds to "try" and avoid gate checking my bag. They always laugh and their persona changes very quickly

I find its only an issue on flights around the US. Americans bring the biggest, fullest, and heaviest carry on bags I have EVER seen. ha ha.
In saying that, I travel with my P4 in a regular back pack, that will slide under the seat in front of me if needed (on most aircraft). My other bag is a messenger/Laptop style bag that I can always manage to find space for somewhere overhead.
Not saying it ever would be an issue but someone did post a video where they were not allowed on a plane with lipo batteries. The airlines found out when they wanted him to check his bag. Granted, they did not allow him to board because of the batteries in general, which was a mistake. But taping them can't hurt, it can only help. It's just a suggestion. If someone does not want to do it, that is up to them.
Yeh he is a Kiwi, I know him. That was his fault for even bring up that he had batteries... It is MUCH better to not even mention what you have, just that it is sensitive, expensive equipment. Then if no space can be found pull the batteries out. ( I flew JetBlue the other day, and the flight attendant was asking each person she was taking bags from if they had Lithium batteries or medication in there as it needed to be removed). Making a fuss, trying to be clever and acting like your stuff is the most important thing on the plane that day gets you -25 bonus points on the Flight Attendant "help you out" scale :/
Basically the Pilot was the jerk... He hated "Drones" because of the current fear mongering... The number of times Ive heard pilots talking about drones and how they will bring a plane down and should be banned, blah blah blah...
Miles traveled means nothing when talking about each boarding. Also, one person's travels is nothing compared to all the people who carry on Lipos.
Do you know how many plane rides/boarding it takes to fly that many miles. ha ha. Granted my copter doesnt always come with me, but even when it doesnt I still travel with a large amount of photography gear as carry on.
My point is, for the amount of time I spend at airports, boarding areas, on aircraft, in Customs and immigration, I have had no problems at all.
Law of averages blah blah.
I read all these posts about airport drama and wonder what people are doing to have such a hard time... Over divulging is usually the number one culprit... Things people dont understand will always scare them, and especially if its anything to do with the current "Drone hysteria" plaguing the hobby at the moment :/
The trick I learned after flying with various Phantoms including P4 over the last 2 1/2 years is that it's best to keep all your wires and chargers separate. If you just have the phantom, batteries, controller and little else in the backpack, then they will see it in their xray machine and not give it a second glance. If you have the pack stuffed with complicated looking electronic stuff then they will inspect fully (although that isn't bad, it just costs some time)..
Totally. Make it as easy as possible to see everything in there as it passes through the xray. My chargers go in side pouches.
battery should be not fully charged? like 2-3 bars?
Pre Phantom days, I travelled with my Lipos at "Storage" charge.
I travel with my P4 batteries at 30%ish.