I’m a travel upgrade expert and everyone makes the same mistake at the airport – it stops you getting bumped up for free

and frequent flyer Jessie Moore said using the self-service check-in machines was a big no-no.

She said: "Skip the self-service machines, if you can.

"One reason why it’s harder to get an upgrade nowadays is that we often check in online then use a self-service machine for bag drop.

"In bypassing the staff altogether, you’re less likely to get an upgrade.

"If you have the option, skip the self-service machine and drop your bags at the check-in desk, where you’ll have a better chance at charming your way into an upgrade."

A British Airways flight attendant backed this up, previously saying: "Your best bet is to ask at the desk when you’re checking in."

A Virgin crew member added that even if you can't get a free upgrade, better seats can be "cheaper at check-in" so is worth the gamble at the airport.

Former airline worker Ben Payne added that it was "virtually impossible" to get an upgrade after check-in due to security purposes.

He added: "When asking for an upgrade, make sure you approach the service desk first, where staff are authorised to make seat changes.

"During peak travel seasons, gate staff may also be authorised to upgrade you."

Despite this, experts have debunked other upgrade myths such as dressing smarter.

Many have warned that the only way to get free upgrades these days is to be a frequent flyer with the airline.

However, you can increase your chances of being the one to get bumped up, including travelling solo and not requesting special meals.

There is another way you may end up in first class if you're in economy - and it's if your seat is broken.