If you find yourself sitting next to a loudly crying child or experiencing constant kicking from the passenger behind you, or even if your seatbelt is malfunctioning, you can discreetly inform the flight attendant, and they will arrange for a better seat change (if available).
Below are some strategies to impress airlines or flight attendants, making it easier for you to secure the best seats on the aircraft.
Pay in Full
When holding your ticket, pay attention to the airline code. This detail determines your passenger type. Each airline has different codes, which passengers can easily look up online. For example, if you have a ticket from Bangkok Airways, code Y means you have paid in full.
Passengers with full payment will be the first to be considered for seat upgrades. Make sure your ticket has a code if you have paid in full. If not, you should also ask ticket agents at the airport to add the code to enhance your chances.

Stick to One Airline
Many airlines worldwide value passenger loyalty. Regularly using the services of one airline is seen as an opportunity to become a fortunate passenger, making it easier to upgrade seats when the occasion arises.
Airlines reward their most loyal customers by upgrading seats. They always know how many miles a customer has flown,” said Ed Hewitt from IndependentTraveler, a travel website.
'Flatter' Flight Attendants
Wear a friendly smile and politely inquire with flight attendants on the plane. If there's a better and available seat, they will surely accommodate your request.
Know When and Where to Choose
Fly during off-peak seasons or weekdays, and you have the chance to be upgraded to a better seat due to fewer passengers.

Dress Sharp
Joe Brancatelli, founder of JoeSentMe, a travel website for business travelers, asserts that 'appearance is crucial and it greatly helps if you want to be upgraded.'
If you appear like a VIP in elegant attire with a black briefcase, your chances of getting a better seat increase significantly. Men can opt for attire resembling businessmen while women should wear simple yet elegant dresses and light makeup.
Birthday Advantage
Inform the airline about your departure date coinciding with your birthday. You'll have the chance to enjoy perks like a better seat on the plane and even complimentary drinks.
Exploit Weaknesses
According to a 2014 survey by Skyscanner, two-thirds of airline staff admitted to agreeing to move passengers who are ill or injured on their legs or arms to better seats if requested. You don't necessarily have to intentionally injure yourself before flying, but if you're already... use this 'trick.'
Utilize Titles
Travelers are more likely to be upgraded to better seats if they add titles like 'pastor,' 'doctor,' 'madam' ahead of their names when purchasing tickets. Thanks to these tricks, a passenger was once upgraded 5 times, specifically buying seat tickets but being upgraded to use a special bed on a flight from Hong Kong to London.
Buy a Seat
In cases where there's little hope of getting a good seat on the plane, pay extra for a nice seat. Many airlines worldwide often offer services to sell good seats on the plane, catering to all traveler needs.
Make Complaints
If you find yourself seated next to a loudly crying child, experiencing constant kicking from the passenger behind you, or even if your seatbelt is malfunctioning, you can discreetly inform the flight attendant, and they will arrange for a better seat change (if available).

According to Vnexpress
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Reference: Travel Handbook from Mytour
MytourJune 23, 2015