Can't help you with the airport situation but thank you for the tip on the Mele quieter mini pc!

When I travel with my AZ-GTi and DSLR (no airports), I only use two or sometimes four batteries.
TalentCell 12V 3000mAh to power AZ-GTi (lasts for a few nights).
TalentCell 12V 6000mAh to power DSLR (lasts for a few nights). If I use this battery to power RPI4 as well then it lasts for just one night.
I use another 12V 3000mAh for a dew heater if needed (one night).
I use another 12V 3000mAh for a monitor if needed (1-2 nights).

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