BA, TUI, and Jet2 let passengers sit together for free as Martin Lewis explains rules

As well as forking out for flights, accommodation and bundles of beachwear, holidaymakers also have to pay to choose where they sit on a plane.

It's a luxury that a lot of people forgo in favour of saving themselves a few quid - but according to Martin Lewis, certain airlines actually allow passengers to do it 'for free'.

The summer holiday season is on the horizon, so there's never been a better time to brush up on the finance expert's advice on how to head abroad without breaking the bank.

And given the current conflict unfolding across the Middle East and the subsequent knock-on effect it is having on the aviation industry, everyone could benefit from browsing through Lewis' top travel tips.

According to Money Saving Expert (MSE), on average, a family of four stump up more than £250 just to pre-book their seats together on return flights.

But in his latest newsletter for MSE, Lewis explained that there is a way that you can possibly get seated next to one another for free after purchasing basic economy tickets.

The consumer champion urged people to take a look at the website's guide to swerving these kind of extra costs by being savvy about which airline you choose to travel with.

Certain airlines offer passengers the ability to sit with each other without paying extra, MSE says (Getty Stock Image)

The first piece of advice is to check in as soon as you physically can - as MSE explains that most airlines will still put you next to the rest of your group if there is availability to do so.

It states that 'all of the major airlines bar Ryanair' said that seat allocations systems will 'always try' to keep people on the same booking together - but obviously, people who have paid to reserve their seat get priority.

Even if you check in the second you are allowed to do, it doesn't guarantee adjacent seats, but 'if you're willing to take a small risk to save some cash, this is a no-brainer'.

MSE advises solo travellers to do the opposite though, as waiting until the last minute can allow them to bag extra-legroom for no extra cost.

Because other passengers didn't want to pay to secure these spots, the airline will then dole these sought-after spots out to the stragglers who checked in at the eleventh hour.

Again, this is a risk - but it can pay off.

Now, onto those heading on a family holiday.

Families can save hundreds with the hack (Getty Stock Image)

Children are 'usually guaranteed a seat next to at least one adult' they are travelling alongside, MSE says.

Airlines should 'aim to sit parents close to children', according to the Civil Aviation Authority (CAA). Failing that, travel firms should try to ensure that youngsters are not more than one aisle or seat row from their guardian.

On top of this, the CAA states that parents shouldn't be stung by extra fees to make sure they're offspring aren't sat at the other end of the plane to them.

But as MSE points out, these are sadly just guidelines rather than firm rules.

However, there are a number of airlines who pledge not to separate parents and children, so choosing to book with these firms can help you avoid paying a premium to accompany your little ones on a flight.

Airlines you should consider if you want to save on seat selecting, according to MSE

British Airways, Tui and Virgin Atlantic 'all guarantee that children under 12 will be seated with at least one adult from their booking', MSE explains, 'although the rest of the group might be split up'.

It adds: "British Airways also lets you choose your seat for free if you're travelling with a child under two. Tui and Virgin warn children may be seated behind or in front of their parents, or be separated from them by an aisle."

Meanwhile, American Airlines and Wizz Air guarantee that children under 15 will be seated with at least one adult from their booking.

MSE goes on to say that Air France 'will do everything it can to make sure that children between two and eleven years old will be seated beside one of the adults from their booking', while 'Jet2, KLM and Norwegian say their systems always try to seat children under 12 with adults from their booking'.

Easyjet also tries to place families together when allocating plane seats - but encourages passengers to check in as early as they can for the best chance of this happening.

"In the case that a family can't sit next to each other, it will make sure each child under 12 is seated 'close to an adult' from their booking," it adds.