Frequent flyers tend to have some favourite practices, like carrying a book, a neck pillow, wearing comfortable clothes, and whatnot, but when it comes to ordering food on a flight, we give in to our temptations. What's better than a hot cup of coffee (black or not) on a long-haul flight? Well, a flight attendant's shocking revelations suggest anything but hot beverages.

In a video from Inside Edition, a flight attendant revealed why she or her colleagues never order warm beverages like coffee or tea when they fly.

"The thing about coffee and tea is that the pipes are rarely cleaned," flight attendant Jamila Hardwick told Inside Edition. Shockingly, airlines are only required to disinfect and flush the water tanks four times a year.

"Airlines work closely with the Environmental Protection Agency (EPA) to ensure that water received from municipalities is safe and to maintain that safety by following rigorous sampling and management requirements, which include disinfection and flushing of the aircraft water tanks on a schedule required by regulation," A4A (Airlines for America) was quoted as saying by the magazine.

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Ordering coffee on a flight? Think againFlickr

If you're hygiene conscious, it's best to avoid ordering warm beverages on the flight. But that's not the only practice you should follow in the air. Hardwick revealed further secrets about airlines, which are not known to customers, even frequent flyers.

Besides coffee and tea, Hardwick also suggests passengers carry a wet tissue to wipe the tray table clean. The flight attendant revealed the tray tables are covered in germs and the cleaning crew doesn't have the time to clean each and every tray between flights. This is the reason why passengers must clean their tray tables before placing anything or even resting on them.

Best practices for frequent flyersReuters

Hardwick also revealed pouring a Diet Coke takes longer to pour in a glass as compared to any other soda. In that time, flight attendants can pour three other drinks. So if you see the crew is taking longer to get to your seat, blame the guys ordering Diet Coke.

Finally, Hardwick offered a helpful hack to get a better seat, which is not rocket science. Being nice to people is often rewarding and this rule holds true in flights. "We are more likely to help you find a better seat if you are nice to us and maybe get an extra drink or two," she said.