Thanks for your suggestions.
The Jackery will not work as it is too big and too high of a capacity for flights.

UPDATE:

I purchased the Omcharge 20.

Jackery Explorer is smaller than Chargetech and can definitely bring on flights. I do it but I have 2x Explorers with me since I fly long distances without ability to recharge between flights

I google Jackets Explorer and this was what showed up:
https://store.jackery.com/products/jackery-powerpro-500w

It doesn't look that small and the capacity is way over what is permitted on flights.

I actually bought this one after my laptop ran dead at a conference that had no where near enough AC outlets in most of the session rooms. I've used it exactly one time, and it is insanely heavy. Also, it never fully charged, even from day one (the charge LEDs are always 1 down no matter how long it charges). It's also noisy when you enable the inverter, and on inverter it's got just enough to recharge a 13" MacBook AIR.

And again, it's heavy. It weighs MORE than my MBA and charger combined, it gets really heavy in a shoulder bag, and even in a backpack it just ends up being unnecessary weight in must circumstances.

If you're often in situations where you're laptop is running dead, it can provide an emergency recharge, but at least for me, it's more trouble than it's worth and it just sits on a shelf now collecting dust. I wish I had never bought it, but it seems like a great idea at the time.

For laptops, it's much, much more efficient to find a DC power bank that charges at the laptop's native charge voltage (usually about 19-20V for PC laptops; I assume similar for Macs.)

There are too many of them to list for PC and while there are fewer that support Magsafe or USB-C PD for Apple, there are still enough of those (and increasingly many on the PD side) that I'd try those first before going to an AC inverter one for laptop use.

I've had a good experience with Dell's first-party "Power Companion" (I have the 18000mah/6 cell version; 65Whr) but it's manufacturer-specific.

This is the one I got


I like it because it charges via USB-C. No need separate charger.