British Airways has apologised to passengers on its flight from Gatwick to Barbados, which was supposed to leave on Sunday evening but eventually took off in the early hours of Monday.
The delay meant the return flight to Gatwick was also held up.
The airline now faces a £290,000 compensation bill.
Earlier in March, a BA Heathrow flight bound for the US was unable to take off for several hours after a mouse was spotted on board.
The Independent reported that the time spent restocking the plane at Gatwick meant the outbound crew were "out of hours and could no longer operate the service within stipulated time limits".
Another crew had to be assembled for the take-off, which caused the initial delay to increase to five hours.
One of the delayed homebound travellers, Jane Gwizdala, told the newspaper that the captain was open about the reason for the delay: "He told us the outbound Gatwick to Bridgetown plane wasn't prepared satisfactorily.
"He said in 26 years of flying he had never had such an experience that impacted on crew and passengers."
A spokeswoman for BA said: "We are sorry customers were delayed after some of the many items needed for the flight weren't loaded on to the aircraft.
"We gave customers refreshment vouchers so they could get something to eat and drink in the terminal and we got them away on their holidays as soon as we could."
EU passengers' rights rules specify people on a long-haul flight delayed by more than three hours are entitled to receive up to 600 euros (£519) in compensation.
With up to 280 people on board each way, it means BA could face a bill of £290,000.
An inadequately stocked toilet roll cupboard and a lack of headphones meant hundreds of holidaymakers were delayed for more than five hours.