Samantha and Pete Sabatino together with their three children were looking forward to their holiday in Florida.
But during the charter flight, six-year-old Emily complained of a funny smell then vomited violently.
In the following fortnight, other family members became ill.
Mum Samantha says she suffered severe flu-like symptoms and breathing problems for the rest of the holiday.
She said: "I just felt absolutely paralysed and couldn't move I had wheezing and lots of crackling in the chest… Just plain, plain plain awful. I really thought something serious was wrong."
She suspected the 'funny smell' was toxic fumes on the plane.
The air breathed on airliners is drawn in past the engines.
It can become polluted by any leaks of engine oil.
'Fume events' are rare but there are no accurate figures of just how many occur each year.
As they waited to fly home, Samantha made a list of 31 passengers who complained they too had been unwell following the flight out.
"I just couldn't believe it.
"I was absolutely astonished that so many people had got sick and they all said their symptoms had started from the plane journey out."
Fourteen of the passengers on that Florida flight are now planning legal action.
They too believe toxic fumes had contaminated the air on board.
Doctors say Samantha didn't have an infection and she's discounted food poisoning.
She says the affected passengers ate different meals, and all she herself had was bread.
And her family are still suffering.
She said: "There has not been one week where all the children have been at school for a full week.
"One's fainted at school, one's been sent home with headache and nausea. The list is endless."
The airline concerned has told Panorama there was no fume event on that flight.
That will now be argued out in court.
Samantha and her fellow passengers have found an American attorney specialising in chemical exposure cases.
Stuart Calwell says the case will focus on his claim that passengers have been damaged by breathing in chemicals contained in jet engine oil.
He said: "Samantha and her fellow passengers exhibit unequivocally signs and symptoms of acute exposure.
"What else explains it? There is no evidence of a viral infection, bacterial infections.
"Most other causes that would produce the long lasting complaints that Samantha and her fellow passengers have have been excluded."