At least 15,000 bags are stranded at Heathrow airport after a third day of cancellations at the new Terminal 5.
The news came after one-fifth of British Airways flights from the troubled terminal were scrapped on Saturday - 67 out of the 330 scheduled.
Many passengers said they departed on flights after being told their luggage would not be travelling. A further 37 flights have been cancelled for Sunday.
The airline has also scrapped its £100 limit for delayed passengers' hotels.
Bags stacked up
BA has confirmed an estimated 15,000 bags are stranded but one source has told the BBC that the number may be closer to 20,000.
The bags are stacked up across all terminals at the airport, after problems with BA flights coming in and out of the new terminal.
Other carriers bringing passengers into Heathrow, to transfer to BA flights, have been asked by the airline to hold on to their bags while it clears the existing backlog.
It is not clear how long the process will take.
The airline said bags for UK destinations would be returned by courier while international luggage would take the next available flight, although ground-based options were also being considered.
"We are looking at ways to get them back as quickly as possible, we are doing everything we can," a BA spokeswoman said.
BA processes 75,000 bags a day through Heathrow and since T5 opened on Thursday, 225,000 items have gone through all their operations at the airport.
Earlier, check-in was suspended for an hour at T5 on Saturday morning, as airport workers attempted to deal with the problem.
The fifth terminal opened amid great fanfare on Thursday, but problems with the baggage handling system and "staff familiarisation" quickly derailed operations.
A total of 208 flights in and out of the terminal were cancelled during the first three days.
Airport operator BAA also confirmed that a "small percentage" of lifts at the terminal were not working on Saturday, but said they were either not in passenger areas or would not interfere with passenger flow.
On one of the delayed planes, passengers on flight BA0662 to Larnaca were held on the tarmac for some four hours before leaving at 1205 GMT.
One, Elizabeth Drury, told the BBC the captain said they would be leaving without any luggage.
They had been told this was because some of the bags initially put on the plane had not been screened properly.
"The whole experience has been meltdown," she said.
A group of school pupils on flight BA285 to San Francisco also said they were told by the airline that their bags were not on board and they could choose whether or not to travel. They were bound for a skiing trip.
"It could ruin it because we are scheduled to start skiing tomorrow," said one schoolgirl, Natalie Bakhurst.
BA apologised to its customers for disruption, and said its operational staff were working tirelessly to make the operation work "robustly".
Afflicted passengers are waiting out delays, or giving up
It advised people to call its information line or check its website before travelling.
The airline had faced criticism over its upper limit on hotel accommodation costs for delayed passengers.
On Thursday evening, leaflets were handed out to blighted passengers saying they were entitled to £100 compensation for two people sharing a hotel room.
But the airline has since said it will consider any "reasonable accommodation cost" claims.
Under 2005 rules, an airline is obliged to supply meals and refreshments, along with accommodation if an overnight stay is required, when a flight is delayed. The Air Transport Users Council said the letter could be in breach of regulations.
The unexpected heavy demand for hotel rooms when the crisis began on Thursday meant that by the evening passengers were being asked to pay £250 for a double room.
But by Saturday night a typical rate for a single room at one of Heathrow's airport hotels was about £80.
BA has set up an information line for T5 passengers: 0800 727800
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