To prevent blood clots during long flights, consider the ‘alphabet’ hack: trace each letter with your foot, wear compression socks, and stand up and walk around every hour. Compression socks are available at Boots for £13.68 or on Amazon for as little as £7.99. Not Your Grandma’s offers fun and colorful compression socks for £15. Boarding on the left side of the aircraft is a tradition that originated from maritime lore.