So far, the longest flights Chloe has taken have been about 5-6 hours long. Traveling to Europe or Asia, however, will take almost twice as long. What if I miscalculate my ice cube rations, and she has to pee en route? I recently came across this suggestion: Carry a stack of wee wee pads with you (and this time, you want the scented ones, that prompt your dog to pee on the pad). If you see your dog showing signs of distress, take her (in her carrier) to the lavatory, spread the pads out on the floor, and encourage her to go.
There are two crucial points to make here. Be careful to (1) choose a time to go when the demand for lavatories is low and the flight is calm, since it may take your dog a moment or two to relax in an en-route airplane lavatory, and (2) cover the floor carefully and thoroughly with wee wee pads. Your fellow passengers will not thank you for leaks. In fact, consider adding to your 3-1-1 bag of permitted carry-on toiletries a 3-oz. bottle of enzymatic cleaner designed for dog clean-ups, and bring it into the lavatory with you. (And of course dispose of the soiled wee wee pads in the wastebasket, not down the toilet.)
I love this idea, but it should be used only for emergencies!