Tamen Jedad Gracia hoped by Tuesday she'd be back with her family in Colombia. The first part of the plan had gone so well.  The 16 year old travelled by herself to Heathrow airport. She'd hooked up with her 18-year-old sister Aliya who'd made an arduous journey from Edinburgh where she's currently studying.

The pair had spent a night in a hotel overlooking Heathrow's north runway and spoken excitedly with their parents about plans for Christmas.

The young women got up early on Saturday. They'd heard the forecast for snow but they were confident their British Airways flight would beat the weather front and by the time the worst of the snow hit, they'd be enjoying a movie 10,000 metres over the Atlantic.

They checked in, did some shopping and made their way onto the plane. It's a long journey to Colombia but at the other end was family waiting to welcome them into the 40 degree Celcius heat.

That's when it started to go wrong. As they sat on the plane an announcement was made that the flight didn't have a captain. Quite why that happened was never fully explained. But they were directed back into the terminal and to the baggage carousel where they had to pick up their luggage. Family were quickly on the case with booking the flights and sorting out hotel rooms, which had suddenly leapt in price.

That was four days ago. Every morning they check in with the airline, always hopeful today might be the day.

'Crazy' scenario

While waiting in the terminal, Tamen was shocked by what she saw: "It's like we were refugees. They were handing out blankets and sandwiches. People were sleeping where they could. It was crazy. It was like something you'd see in a war".

Aliya tried to get help from the airline. "They were awful. Really bad. It's as if they don't want to know."

And so after spending some time in the internet cafe at the hotel and making long and expensive calls, there was a plan F.

Aliya told me, "We're heading by train to Birmingham, from there we fly to Amsterdam and on to Malaga. I've found out we can go from there direct to Panama. And then there is a connection to Colombia. If all goes well we'll be there by Christmas Eve."

Yet there are thousands who are hanging on - hopeful the weather will turn or the airline will open up seats and their holiday or their trip home will suddenly be back on.

At Heathrow it seems as if things are getting better. Flights are taking off and landing every few minutes.

But the airport is running at only a third of its capacity, which means that every hour the situation is getting worse and that thousands more are being delayed and frustrated and that plans for this holiday season are being ruined.