I read a statistic last week that still has me reeling:
Airlines use about 1 million disposable cups every 6 hours!
Bring your own reusable bottles on your trip and have the flight attendant fill 'er up. If you don't have one, go to World Wildlife Fund's website here, make a donation, and receive two cute water bottles with the panda logo. They're essentially "free" since your donation amount is tax deductible.
You can read the whole article about airline waste here: