Could this be the secret to getting a free upgrade on a flight?

After a long wait in departures and a sweaty, disappointing bacon and chicken wrap from WH Smith, there is little more pleasurable than hearing the words "would you like an upgrade, sir?" uttered by an air steward.

But those six magic words are very rarely uttered. So what's the secret to securing that move from economy to business or first class?

Cosmo's Catriona Harvey-Jenner was recently on a flight with BA when she decided to "corner" some flight attendants for some advice. This is what they told her:

All you do, apparently, to give you a better chance of being upgraded is to avoid pre-selecting a seat when you check in online prior to your flight.

Could it really be hat simple? Well, it certainly sounds like it could increase your chances.

According to Jonathan Marks, a global investment banker who has a habit of getting free upgrades, there are at least eight ways to go about it:

1. Ask for one (makes sense, to be fair)

2. "Engage in check-in banter"

3. Travel solo

4. If the flight is over-booked volunteer for a later one

5. Get a loyalty card

6. Travel during holiday season when business class is less likely to be used

7. Look for online deals

8. Pretend it's your honeymoon

More: Pilots reveal the 7 most bizarre things they've ever seen while flying