Hugh,
I used to be an airline pilot, so I’ve spent plenty of time in airports and hotels. Let your readers know, one inexpensive way to pick up an extra cell phone charger is to ask the front desk at the hotel. Previous guests accidentally leave their chargers, and the hotel stores them in a box. Most guests never return for them (I have left a couple myself), and the hotel either has to give them away or dispose of them. Just ask if you can run through their “box-o-chargers”; every hotel has one. – R from Texas