I'm a frequent flyer who's flown over 20 times this year. Here are 5 mistakes I've seen passengers make whenever they travel.

The author has boarded more than 20 planes this year alone.Marielle Descalsota/Insider

• I've traveled on 24 flights to nine countries this year.
• As a frequent flyer, I've made several mistakes while traveling through airports.

As Insider's travel reporter in Singapore, I fly regularly for work and leisure. This year alone, I've taken some 24 flights to nine different countries, including Taiwan, Thailand, and the Philippines.

I've flown low-cost airlines like Malaysia's AirAsia and the Philippines's Cebu Pacific, as well as five-star airlines like Singapore Airlines. And on all of these flights, I've witnessed passengers doing things that lead to unnecessarily uncomfortable experiences.

No matter what airline, passengers can follow several rules and guidelines for a smooth journey. Here are five of the most common mistakes passengers make when they fly and what they can do to avoid them.