A savvy traveller has won approval with their ingenious airport hack to keep hydrated without splashing the cash on expensive terminal beverages.

Diving into a Reddit discussion, ‘What hacks did you find out to improve your flight/airport experience?’ one globetrotter unfolded a clever tip that could see your wallet heave a sigh of relief in transit lounges.

They said: “You can’t bring a full water bottle through airport security, but you can bring an empty one. Most airports have water bottle…