My Medella pump came with a battery pack. That way I could use it anywhere that’s more or less private, even without an outlet. I’ve pumped in airplane bathrooms, while driving in the car, in the airport bathroom stalls (and a bunch of other bathroom stalls). My favorite was pumping at the event held at a horse track. Nothing like the smell of horse manure to get the let-down going… One good thing is seeing the priceless look on male TSA officers when you tell them it’s breastmilk! Saying the B word gets you through the security line faster than TSA Pre!