Researchers advise airline passengers to never drink water aboard an airplane. But what about the potable water that's used in tea and coffee? Many flight attendants also recommend sticking to bottled water or beverages only. This is because the coffee and tea on board are filled with water from tanks that aren't cleaned frequently. Many major airlines even tested their water and found E. coli and coliform bacteria present.
It's probably best to ask for a water bottle next time you're thirsty during your flight!