When we checked, a family of four on a British Airways flight from London to Tenerife would have paid £112 to pre-select standard seats. For extra legroom, this rose to £192.
In fact, we found that most major airlines will automatically seat you with the people you booked with. For easyJet the figure was 93% and for Jet2 90%.
Airlines most likely to split you up
The chances of being separated in the cabin are higher if you fly with Ryanair or Wizz Air.
Only 66% of Ryanair passengers who booked in groups or pairs, without paying for seat selection, said they ended up together. For Wizz Air that figure was just 61%.
Are you legally entitled to sit with your family?
There’s no legal right to sit next to your family, not even children. The Civil Aviation Authority (CAA) says: ‘Young children and infants who are accompanied by adults should ideally be seated in the same seat row as the adult. Where this is not possible, children should be separated by no more than one seat row from accompanying adults.’
Most airlines will automatically sit you next to your offspring, although Ryanair does this by insisting that an accompanying adult has to pay for seat selection.
The cost of sitting together - and your odds of beating the systemIn October 2022 we asked 8,046 Which? members and the public about their experience of flying in the past two years. Costs taken from a London to Tenerife flight for June 2023, booked in February. *Per person, each way. Doesn't include extra legroom
source https://www.which.co.uk/news/article/why-airline-seat-selection-is-a-waste-of-money-aCUfB4w0avss