India, July 12 -- The beverage cart may be one of air travel's simplest pleasures.

While seatback televisions, music, and books can keep you entertained, there's nothing like a refreshing drink to remedy the dry mouth that comes with being confined to a pressurized metal tube for a few hours.

But there is one drink order that raises eyebrows, even among the flight attendants who serve it: coffee.

"Coffee has certainly topped the list of 'do not order' items on a plane," confirmed an anonymous American Airlines flight attendant in an email to Travel + Leisure. "That said, its negative reputation does come with a bit of misinformation."

The case against a cup o' joe is often twofold: The water used to make the coffee is supposedly t...