I've discovered that one thing that helps my ears with plane flights is to drink several small sips of water during takeoff and landing. I could buy water at the airport, or take an empty bottle and fill it, but I'd really like to find a water bottle small enough to take through security--that way I won't have to worry about remembering to get water once I'm at the airport. I've been doing some searching and have found some small cute water bottles, but nothing small enough to put in a 3-1-1 bag (needs to be 100ml/3.4oz or smaller).
Do you have any ideas? I've also been looking at little bottles meant to hold travel shampoo and such, but the ones I've seen have had flip-top lids and I feel like any sort of complication to the lid will make it more likely that the bottle will leak.