My wife and I travel a lot and both of us have battery backup for our phones. I see people always charging their phones before a flight. It’s so much easier to throw one of these in your backpack.
You could even charge a modern Macbook with these. My MacBook charges fine (just a little slow) with an 18 or 20w charger.
Was traveling back from international trip and supposedly many countries don’t allow you to fly with them. I had to fork over all 5 of my banks my family were carrying 
That is true. The batteries can combust or leak. It tells you in the airlines cans & cannots of what you’re able to carry on.
Charging your phone in an airport using the plug in ports instead of your charger is a massive risk for being hacked. You can confirm via Google. Either pack something like this or do what I do with a 65w charger that also can charge my 14" notebook and phone as hotspot while working.
lol.
And the best way to charge up your phone for a flight is to use your own ac adapter to charge it from an airport ac outlet (there for floor cleaning) and carry an extension cord or 3-outlet cube, in case others need to share. Also top off your battery bank before boarding. And then use one or the other as needed (and available) on board.
For the most part, TSA regs are somewhere around 25,000-30,000 mah. There can also be different restrictions for checked vs carry-on. Of course, other countries can set other requirements. Check before you pack, or during your arrival, for your departure.
How heavy is it
So do I have to place 2 separate orders to get to use it twice?
Besides phones, I also have an LED lamp and a fan (9") that have a USB cable - when we get a power bump it’s great to have these backups to run them off of. We have 4+ currently.
Do these automatically turn off after a period of time like the Onn 20,000mAh?
Hi there. Here it is on Amazon. I don’t see any mention of that feature.
https://www.amazon.com/dp/B0BYSCQ4CD